JP2005292952A

Storage system, storage device and remote copy method

Abstract

Problem to be solved.To safely copy snap shot data.

Solution.A first data transferring part transmits update data written in a first application volume to a second data transferring part, and the second transferring part stores the update data in a second application volume, and stores difference data written in the storage position of the update data of the second application volume in a second difference volume, and updates a second management information storage part. Afterwards, the completion of the data update is noticed to the first data transferring part, and the first data transferring part receives the notice of the completion of the data update from the second data transferring part, and stores the update data in the update position of the first application volume, and stores the difference data in the first difference volume, and updates the first management information storing part.

Term

Term ended

Projected expiry passed 31 March 2024, 2.5 years ago.

20 claims: 16 independent, 4 dependent

1
A first disk subsystem having a disk drive used for normal operation, a first file server that controls data input / output to the first disk subsystem, and data stored in the first disk subsystem. A second disk subsystem having a disk drive for storing duplicates, a second file server that controls the input and output of data to the second disk subsystem, the first disk subsystem, and the second disk subsystem. The first disk subsystem is provided with a communication line connecting between the first operation volume, and the first difference data for storing the difference data between the first operation volume in which normal reading and writing is performed and the snapshot of the first operation volume. A first management information holding unit that manages the volume, the difference data, and a first data transfer unit that transfers data between the second disk subsystem are provided. The second disk subsystem includes a second operational volume that stores a copy of the data stored in the first operational volume, a second differential volume that stores the difference data of the snapshot of the second operational volume, and the like. A second management information holding unit that manages the difference data and a second data transfer unit that transfers data between the second disk subsystem are provided;通常運用に供されるディスクドライブを有する第1ディスクサブシステムと、前記第1ディスクサブシステムへのデータの入出力を制御する第1ファイルサーバと、前記第1ディスクサブシステムに記憶されるデータの複製を記憶するディスクドライブを有する第2ディスクサブシステムと、前記第2ディスクサブシステムへのデータの入出力を制御する第2ファイルサーバと、前記第1ディスクサブシステムと前記第2ディスクサブシステムとの間を接続する通信回線と、を備え、前記第1ディスクサブシステムには、通常の読み書きが行われる第1運用ボリュームと、前記第1運用ボリュームのスナップショットの差分データを記憶する第1差分ボリュームと、前記差分データを管理する第1管理情報保持部と、前記第2ディスクサブシステムとの間でデータを転送する第1データ転送部と、が設けられ、前記第2ディスクサブシステムには、前記第1運用ボリュームに記憶されるデータの複製を記憶する第2運用ボリュームと、前記第2運用ボリュームのスナップショットの差分データを記憶する第2差分ボリュームと、前記差分データを管理する第2管理情報保持部と、前記第2ディスクサブシステムとの間でデータを転送する第2データ転送部と、が設けられ;The first file server and the second file server each transmit and receive data and control signals between the host input / output control unit that transmits and receives data and control signals to and from the host and the disk subsystem. The disk input / output control unit, the cache memory that temporarily stores the data transmitted / received between the host input / output control unit and the disk input / output control unit, and the operation of the file server by executing the control program. It is a storage system provided with a CPU for controlling the control program and a memory for storing the control program;前記第1ファイルサーバ及び前記第2ファイルサーバの各々には、ホストとの間でデータや制御信号を送受信するホスト入出力制御部と、前記ディスクサブシステムとの間でデータや制御信号を送受信するディスク入出力制御部と、前記ホスト入出力制御部と前記ディスク入出力制御部との間で送受信されるデータを一時的に記憶するキャッシュメモリと、制御プログラムを実行することによって前記ファイルサーバの動作を制御するCPUと、前記制御プログラムが記憶されるメモリと、が設けられるストレージシステムであって;The first data transfer unit is of the update data written to the first operating volume, the update position where the update data is written, the difference data written at the update position of the first operation volume, and the difference data. The management information indicating the storage position is collectively transmitted to the second data transfer unit;前記第1データ転送部は、前記第1運用ボリュームに書き込まれる更新データ、前記更新データが書き込まれる更新位置、前記第1運用ボリュームの前記更新位置に書き込まれている差分データ、及び前記差分データの格納位置を示す管理情報を一まとめにして前記第2データ転送部に送信し;The second data transfer unit stores the update data transmitted from the first data transfer unit at the update position of the second operation volume, and the difference data transmitted from the first data transfer unit is stored in the second data transfer unit. It is stored in the difference volume, the second management information holding unit is updated based on the management information transmitted from the first data transfer unit, and then the completion of the data update is notified to the first data transfer unit;前記第2データ転送部は、前記第1データ転送部から送信された更新データを前記第2運用ボリュームの前記更新位置に格納し、前記第1データ転送部から送信された差分データを前記第2差分ボリュームに格納し、前記第1データ転送部から送信された管理情報に基づいて前記第2管理情報保持部を更新し、その後、データ更新の完了を前記第1データ転送部に通知し;When the first data transfer unit receives the data update completion notification from the second data transfer unit, the first data transfer unit stores the update data at the update position of the first operation volume, and stores the difference data in the first difference volume. A storage system that stores and updates the first management information holding unit. 前記第1データ転送部は、前記第2データ転送部からデータ更新完了通知を受信すると、前記更新データを前記第1運用ボリュームの前記更新位置に格納し、前記差分データを前記第1差分ボリュームに格納し、前記第1管理情報保持部を更新するストレージシステム。
2
A first disk subsystem having a disk drive for normal operation, a second disk subsystem having a disk drive storing a copy of data stored in the first disk subsystem, and the first disk subsystem. The first disk subsystem is provided with a communication line connecting the data and the second disk subsystem, and the first disk subsystem is the difference between the snapshot of the first operation volume for normal reading and writing and the snapshot of the first operation volume. A first differential volume for storing data, a first management information holding unit for managing the differential data, and a first data transfer unit for transferring data between the second disk subsystem are provided. The second disk subsystem includes a second operational volume that stores a copy of the data stored in the first operational volume, a second differential volume that stores the difference data of the snapshot of the second operational volume, and the above. It is a storage system provided with a second management information holding unit that manages difference data and a second data transfer unit that transfers data between the second disk subsystem;通常運用に供されるディスクドライブを有する第1ディスクサブシステムと、前記第1ディスクサブシステムに記憶されるデータの複製を記憶するディスクドライブを有する第2ディスクサブシステムと、前記第1ディスクサブシステムと前記第2ディスクサブシステムとの間を接続する通信回線と、を備え、前記第1ディスクサブシステムには、通常の読み書きを行う第1運用ボリュームと、前記第1運用ボリュームのスナップショットの差分データを記憶する第1差分ボリュームと、前記差分データを管理する第1管理情報保持部と、前記第2ディスクサブシステムとの間でデータを転送する第1データ転送部と、が設けられ、前記第2ディスクサブシステムには、前記第1運用ボリュームに記憶されるデータの複製を記憶する第2運用ボリュームと、前記第2運用ボリュームのスナップショットの差分データを記憶する第2差分ボリュームと、前記差分データを管理する第2管理情報保持部と、前記第2ディスクサブシステムとの間でデータを転送する第2データ転送部と、が設けられるストレージシステムであって;The first data transfer unit transmits update data written to the first operating volume to the second data transfer unit;前記第1データ転送部は、前記第1運用ボリュームに書き込まれる更新データを前記第2データ転送部に送信し;The second data transfer unit stores the update data in the second operation volume, and stores the difference data written in the update data storage position of the second operation volume in the second difference volume. The second management information holding unit is updated, and then the completion of the data update is notified to the first data transfer unit;前記第2データ転送部は、前記更新データを前記第2運用ボリュームに格納し、前記第2運用ボリュームの前記更新データの格納位置に書き込まれている差分データを前記第2差分ボリュームに格納し、前記第2管理情報保持部を更新し、その後、データ更新の完了を前記第1データ転送部に通知し;When the first data transfer unit receives the data update completion notification from the second data transfer unit, the first data transfer unit stores the update data at the update position of the first operation volume, and stores the difference data in the first difference volume. A storage system that stores in and updates the first management information holding unit. 前記第1データ転送部は、前記第2データ転送部からのデータ更新完了通知を受信すると、前記更新データを前記第1運用ボリュームの前記更新位置に格納し、前記差分データを前記第1差分ボリュームに格納し、前記第1管理情報保持部を更新するストレージシステム。
3
The first data transfer unit is of the update data written to the first operating volume, the update position where the update data is written, the difference data written at the update position of the first operation volume, and the difference data. The management information indicating the storage position is collectively transmitted to the second data transfer unit;前記第1データ転送部は、前記第1運用ボリュームに書き込まれる更新データ、前記更新データが書き込まれる更新位置、前記第1運用ボリュームの前記更新位置に書き込まれている差分データ、及び前記差分データの格納位置を示す管理情報を一まとめにして前記第2データ転送部に送信し;The second data transfer unit stores the update data transmitted from the first data transfer unit at the update position of the second operation volume, and the difference data transmitted from the first data transfer unit is stored in the second data transfer unit. A claim that stores the data in a difference volume, updates the second management information holding unit based on the management information transmitted from the first data transfer unit, and then notifies the first data transfer unit of the completion of the data update. The storage system described in 2. 前記第2データ転送部は、前記第1データ転送部から送信された更新データを前記第2運用ボリュームの前記更新位置に格納し、前記第1データ転送部から送信された差分データを前記第2差分ボリュームに格納し、前記第1データ転送部から送信された管理情報に基づいて前記第2管理情報保持部を更新し、その後、データ更新の完了を前記第1データ転送部に通知する請求項2に記載のストレージシステム。
4
The second data transfer unit compares the difference data transmitted from the first data transfer unit with the difference data stored in the update position of the second difference volume, and the two difference data match. If so, the update data transmitted from the first data transfer unit is stored in the update position of the second operation volume, and the difference data transmitted from the first data transfer unit is stored in the second difference volume. The management information stored and transmitted from the first data transfer unit is compared with the management information generated based on the storage position of the difference data in the second difference volume, and both management information match. If so, claim 3 updates the second management information holding unit based on the management information transmitted from the first data transfer unit, and then notifies the first data transfer unit of the completion of the data update. Described storage system. 前記第2データ転送部は、前記第1データ転送部から送信された差分データと、前記第2差分ボリュームの前記更新位置に格納されている差分データとを比較し、前記両差分データが一致している場合に、前記第1データ転送部から送信された更新データを前記第2運用ボリュームの前記更新位置に格納し、前記第1データ転送部から送信された差分データを前記第2差分ボリュームに格納し、前記第1データ転送部から送信された管理情報と、前記差分データの第2差分ボリュームへの格納位置に基づいて生成された管理情報とを比較し、前記両管理情報が一致している場合に、前記第1データ転送部から送信された管理情報に基づいて前記第2管理情報保持部を更新し、その後、データ更新の完了を前記第1データ転送部に通知する請求項3に記載のストレージシステム。
5
The first data transfer unit determines the load status of the communication line, and when it is determined that the load of the communication line is large, the update data written to the first operating volume and the update to which the update data is written are written. Send the location to the second data transfer unit;前記第1データ転送部は、前記通信回線の負荷状況を判定し、前記通信回線の負荷が大きいと判定した場合は、前記第1運用ボリュームに書き込まれる更新データ、及び前記更新データが書き込まれる更新位置を前記第2データ転送部に送信し;The second data transfer unit reads the difference data stored in the update position of the second operation volume and stores it in the second difference volume, and the update data transmitted from the first data transfer unit is described. The second operation volume is stored in the update position, the second management information holding unit is updated based on the storage position of the difference data in the second difference volume, and then the completion of the data update is completed by the first data transfer. Notify the department;前記第2データ転送部は、前記第2運用ボリュームの前記更新位置に格納されている差分データを読み出して前記第2差分ボリュームに格納し、前記第1データ転送部から送信された更新データを前記第2運用ボリュームの前記更新位置に格納し、前記差分データの第2差分ボリュームへの格納位置に基づいて前記第2管理情報保持部を更新し、その後、データ更新の完了を前記第1データ転送部に通知し;When the first data transfer unit receives the data update completion notification from the second data transfer unit, the first data transfer unit stores the update data at the update position of the first operation volume, and stores the difference data in the first difference volume. The storage system according to claim 2, which is stored in the data and updates the first management information holding unit. 前記第1データ転送部は、前記第2データ転送部からのデータ更新完了通知を受信すると、前記更新データを前記第1運用ボリュームの前記更新位置に格納し、前記差分データを前記第1差分ボリュームに格納し、前記第1管理情報保持部を更新する請求項2に記載のストレージシステム。
6
The first data transfer unit determines the load status of the communication line, and when it is determined that the load of the communication line is small, the update data written to the first operating volume and the update position where the update data is written. , The difference data written in the update position of the first operation volume and the management information indicating the storage position of the difference data are collectively transmitted to the second data transfer unit;前記第1データ転送部は、前記通信回線の負荷状況を判定し、前記通信回線の負荷が小さいと判定した場合は、前記第1運用ボリュームに書き込まれる更新データ、前記更新データが書き込まれる更新位置、前記第1運用ボリュームの前記更新位置に書き込まれている差分データ、及び前記差分データの格納位置を示す管理情報を一まとめにして前記第2データ転送部に送信し;The second data transfer unit compares the difference data transmitted from the first data transfer unit with the difference data stored in the update position of the second difference volume, and the two difference data match. If so, the update data transmitted from the first data transfer unit is stored in the update position of the second operation volume, and the difference data transmitted from the first data transfer unit is stored in the second difference volume. The management information stored and transmitted from the first data transfer unit is compared with the management information generated based on the storage position of the difference data in the second difference volume, and both management information match. If so, the second management information holding unit is updated based on the management information transmitted from the first data transfer unit, and then the completion of the data update is notified to the first data transfer unit;前記第2データ転送部は、前記第1データ転送部から送信された差分データと、前記第2差分ボリュームの前記更新位置に格納されている差分データとを比較し、前記両差分データが一致している場合に、前記第1データ転送部から送信された更新データを前記第2運用ボリュームの前記更新位置に格納し、前記第1データ転送部から送信された差分データを前記第2差分ボリュームに格納し、前記第1データ転送部から送信された管理情報と、前記差分データの第2差分ボリュームへの格納位置に基づいて生成された管理情報とを比較し、前記両管理情報が一致している場合に、前記第1データ転送部から送信された管理情報に基づいて前記第2管理情報保持部を更新し、その後、データ更新の完了を前記第1データ転送部に通知し;When the first data transfer unit receives the data update completion notification from the second data transfer unit, the first data transfer unit stores the update data in the update position of the first operation volume, and stores the difference data in the first difference volume. The storage system according to claim 2, which stores and updates the first management information holding unit. 前記第1データ転送部は、前記第2データ転送部からデータ更新完了通知を受信すると、前記更新データを前記第1運用ボリュームの前記更新位置に格納し、前記差分データを前記第1差分ボリュームに格納し、前記第1管理情報保持部を更新する請求項2に記載のストレージシステム。
7
The first data transfer unit transmits the update data written to the first operating volume and the update position where the update data is written to the second data transfer unit;前記第1データ転送部は、前記第1運用ボリュームに書き込まれる更新データ、及び前記更新データが書き込まれる更新位置を前記第2データ転送部に送信し;The second data transfer unit reads the difference data stored in the update position of the second operation volume and stores it in the second difference volume, and the update data transmitted from the first data transfer unit is described. The second operation volume is stored in the update position, the second management information holding unit is updated based on the storage position of the difference data in the second difference volume, and then the completion of the data update is completed by the first data transfer. The storage system according to claim 2, which is notified to the department. 前記第2データ転送部は、前記第2運用ボリュームの前記更新位置に格納されている差分データを読み出して前記第2差分ボリュームに格納し、前記第1データ転送部から送信された更新データを前記第2運用ボリュームの前記更新位置に格納し、前記差分データの第2差分ボリュームへの格納位置に基づいて前記第2管理情報保持部を更新し、その後、データ更新の完了を前記第1データ転送部に通知する請求項2に記載のストレージシステム。
8
A first storage device having a disk drive used for normal operation, a second storage device having a disk drive for storing a copy of data stored in the first storage device, the first storage device, and the second storage device. A communication line for connecting to and from the storage device is provided, and the first storage device stores the difference data between the first operation volume on which normal reading and writing is performed and the snapshot of the first operation volume. A difference volume, a first management information holding unit that manages the difference data, and a first data transfer unit that transfers data between the second storage device are provided, and the second storage device is provided. , A second operational volume that stores a copy of the data stored in the first operational volume, a second differential volume that stores the difference data of the snapshot of the second operational volume, and a second that manages the differential data. A storage device used in a storage system provided with a management information holding unit and a second data transfer unit that transfers data between the second storage device;通常運用に供されるディスクドライブを有する第1ストレージ装置と、前記第1ストレージ装置に記憶されるデータの複製を記憶するディスクドライブを有する第2ストレージ装置と、前記第1ストレージ装置と前記第2ストレージ装置との間を接続する通信回線と、を備え、前記第1ストレージ装置には、通常の読み書きが行われる第1運用ボリュームと、前記第1運用ボリュームのスナップショットの差分データを記憶する第1差分ボリュームと、前記差分データを管理する第1管理情報保持部と、前記第2ストレージ装置との間でデータを転送する第1データ転送部と、が設けられ、前記第2ストレージ装置には、前記第1運用ボリュームに記憶されるデータの複製を記憶する第2運用ボリュームと、前記第2運用ボリュームのスナップショットの差分データを記憶する第2差分ボリュームと、前記差分データを管理する第2管理情報保持部と、前記第2ストレージ装置との間でデータを転送する第2データ転送部と、が設けられるストレージシステムに用いられるストレージ装置であって;When the first data transfer unit transmits the update data written to the first operating volume to the second data transfer unit and receives the data update completion notification from the second data transfer unit, the first data transfer unit receives the update data. 1 A storage device that stores the difference data in the update position of the operation volume, stores the difference data in the first difference volume, and updates the first management information holding unit. 前記第1データ転送部は、前記第1運用ボリュームに書き込まれる更新データを前記第2データ転送部に送信し、データ更新完了通知を前記第2データ転送部から受信すると、前記更新データを前記第1運用ボリュームの前記更新位置に格納し、前記差分データを前記第1差分ボリュームに格納し、前記第1管理情報保持部を更新するストレージ装置。
12
A first storage device having a disk drive used for normal operation, a second storage device having a disk drive for storing a copy of data stored in the first storage device, the first storage device, and the second storage device. A communication line for connecting to and from the storage device is provided, and the first storage device stores the difference data between the first operation volume on which normal reading and writing is performed and the snapshot of the first operation volume. A difference volume, a first management information holding unit that manages the difference data, and a first data transfer unit that transfers data between the second storage device are provided, and the second storage device is provided. , A second operational volume that stores a copy of the data stored in the first operational volume, a second differential volume that stores the difference data of the snapshot of the second operational volume, and a second that manages the differential data. A storage device used in a storage system provided with a management information holding unit and a second data transfer unit that transfers data between the second storage device;通常運用に供されるディスクドライブを有する第1ストレージ装置と、前記第1ストレージ装置に記憶されるデータの複製を記憶するディスクドライブを有する第2ストレージ装置と、前記第1ストレージ装置と前記第2ストレージ装置との間を接続する通信回線と、を備え、前記第1ストレージ装置には、通常の読み書きが行われる第1運用ボリュームと、前記第1運用ボリュームのスナップショットの差分データを記憶する第1差分ボリュームと、前記差分データを管理する第1管理情報保持部と、前記第2ストレージ装置との間でデータを転送する第1データ転送部と、が設けられ、前記第2ストレージ装置には、前記第1運用ボリュームに記憶されるデータの複製を記憶する第2運用ボリュームと、前記第2運用ボリュームのスナップショットの差分データを記憶する第2差分ボリュームと、前記差分データを管理する第2管理情報保持部と、前記第2ストレージ装置との間でデータを転送する第2データ転送部と、が設けられるストレージシステムに用いられるストレージ装置であって;The second data transfer unit receives the update data written to the first operation volume from the first data transfer unit, stores the update data in the second operation volume, and updates the second operation volume. The difference data written in the data storage position is stored in the second difference volume, the second management information holding unit is updated, and then the data update completion notification for causing the first storage device to update the data. A storage device that sends. 前記第2データ転送部は、前記第1運用ボリュームに書き込まれる更新データを前記第1データ転送部から受信し、前記更新データを前記第2運用ボリュームに格納し、前記第2運用ボリュームの前記更新データの格納位置に書き込まれている差分データを前記第2差分ボリュームに格納し、前記第2管理情報保持部を更新し、その後、前記第1ストレージ装置にデータを更新させるためのデータ更新完了通知を送信するストレージ装置。
13
The second data transfer unit is of the update data written to the first operating volume, the update position where the update data is written, the difference data written at the update position of the first operation volume, and the difference data. A signal in which management information indicating the storage position is collected is received from the first data transfer unit;前記第2データ転送部は、前記第1運用ボリュームに書き込まれる更新データ、前記更新データが書き込まれる更新位置、前記第1運用ボリュームの前記更新位置に書き込まれている差分データ、及び前記差分データの格納位置を示す管理情報が一まとめにされた信号を前記第1データ転送部から受信し;The received update data is stored in the update position of the second operation volume, the received difference data is stored in the second difference volume, and the second management information holding unit is stored based on the received management information. The storage device according to claim 12, which is updated and then notifies the first data transfer unit of the completion of the data update. 前記受信した更新データを前記第2運用ボリュームの前記更新位置に格納し、前記受信した差分データを前記第2差分ボリュームに格納し、前記受信した管理情報に基づいて前記第2管理情報保持部を更新し、その後、前記データ更新の完了を前記第1データ転送部に通知する請求項12に記載のストレージ装置。
15
When the first data transfer unit determines that the load on the communication line is large, the second data transfer unit determines the update data written to the first operation volume and the update position where the update data is written. The difference data received from the first data transfer unit and stored in the update position of the second operation volume is read and stored in the second difference volume, and the received update data is stored in the second operation volume. Request to store in the update position, update the second management information holding unit based on the storage position of the difference data in the second difference volume, and then notify the first data transfer unit of the completion of the data update. Item 12. The storage device according to item 12. 前記第2データ転送部は、前記第1データ転送部が前記通信回線の負荷が大きいと判定した場合は、前記第1運用ボリュームに書き込まれる更新データ、及び前記更新データが書き込まれる更新位置を前記第1データ転送部から受信し、前記第2運用ボリュームの前記更新位置に格納されている差分データを読み出して前記第2差分ボリュームに格納し、前記受信した更新データを前記第2運用ボリュームの前記更新位置に格納し、前記差分データの第2差分ボリュームへの格納位置に基づいて前記第2管理情報保持部を更新し、その後、前記データ更新の完了を前記第1データ転送部に通知する請求項12に記載のストレージ装置。
16
When the first data transfer unit determines that the load on the communication line is small, the second data transfer unit determines the update data written to the first operation volume, the update position where the update data is written, and the second data transfer unit. (1) A signal in which the difference data written in the update position of the operating volume and the management information indicating the storage position of the difference data are collected is received from the first data transfer unit;前記第2データ転送部は、前記第1データ転送部が前記通信回線の負荷が小さいと判定した場合は、前記第1運用ボリュームに書き込まれる更新データ、前記更新データが書き込まれる更新位置、前記第1運用ボリュームの前記更新位置に書き込まれている差分データ、及び前記差分データの格納位置を示す管理情報が一まとめにされた信号を前記第1データ転送部から受信し;The received difference data is compared with the difference data stored in the update position of the second difference volume, and when both difference data match, the first data transfer unit transmits the difference data. The update data is stored in the update position of the second operation volume, the received difference data is stored in the second difference volume, and the received management information and the storage position of the difference data in the second difference volume are stored. Compares with the management information generated based on, and if both management information match, the second management information holding unit is updated based on the management information transmitted from the first data transfer unit. After that, the storage device according to claim 12, which notifies the first data transfer unit of the completion of the data update. 前記受信した差分データと、前記第2差分ボリュームの前記更新位置に格納されている差分データとを比較し、前記両差分データが一致している場合に、前記第1データ転送部から送信された更新データを前記第2運用ボリュームの前記更新位置に格納し、前記受信した差分データを前記第2差分ボリュームに格納し、前記受信した管理情報と、前記差分データの第2差分ボリュームへの格納位置に基づいて生成された管理情報とを比較し、前記両管理情報が一致している場合に、前記第1データ転送部から送信された管理情報に基づいて前記第2管理情報保持部を更新し、その後、前記データ更新の完了を前記第1データ転送部に通知する請求項12に記載のストレージ装置。
17
The second data transfer unit receives the update data written to the first operating volume and the update position where the update data is written from the first data transfer unit;前記第2データ転送部は、前記第1運用ボリュームに書き込まれる更新データ、及び前記更新データが書き込まれる更新位置を前記第1データ転送部から受信し;The difference data stored in the update position of the second operation volume is read out and stored in the second difference volume, the received update data is stored in the update position of the second operation volume, and the difference data is stored. 12. The storage device according to claim 12, which updates the second management information holding unit based on the storage position in the second difference volume, and then notifies the first data transfer unit of the completion of the data update. 前記第2運用ボリュームの前記更新位置に格納されている差分データを読み出して前記第2差分ボリュームに格納し、前記受信した更新データを前記第2運用ボリュームの前記更新位置に格納し、前記差分データの第2差分ボリュームへの格納位置に基づいて前記第2管理情報保持部を更新し、その後、前記データ更新の完了を前記第1データ転送部に通知する請求項12に記載のストレージ装置。
18
A first disk subsystem having a disk drive for normal operation, a second disk subsystem having a disk drive storing a copy of data stored in the first disk subsystem, and the first disk subsystem. A communication line connecting the data and the second disk subsystem is provided, and the first disk subsystem includes a first operation volume in which normal reading and writing is performed, and a snapshot of the first operation volume. A first difference volume for storing difference data, a first management information holding unit for managing the difference data, and a first data transfer unit for transferring data between the second disk subsystem are provided. The second disk subsystem includes a second operational volume that stores a copy of the data stored in the first operational volume, a second differential volume that stores the difference data of the snapshot of the second operational volume, and the like. It is a remote copy method used in a storage system provided with a second management information holding unit that manages the difference data and a second data transfer unit that transfers data between the second disk subsystem;通常運用に供されるディスクドライブを有する第1ディスクサブシステムと、前記第1ディスクサブシステムに記憶されるデータの複製を記憶するディスクドライブを有する第2ディスクサブシステムと、前記第1ディスクサブシステムと前記第2ディスクサブシステムとの間を接続する通信回線と、を備え、前記第1ディスクサブシステムには、通常の読み書きが行われる第1運用ボリュームと、前記第1運用ボリュームのスナップショットの差分データを記憶する第1差分ボリュームと、前記差分データを管理する第1管理情報保持部と、前記第2ディスクサブシステムとの間でデータを転送する第1データ転送部と、が設けられ、前記第2ディスクサブシステムには、前記第1運用ボリュームに記憶されるデータの複製を記憶する第2運用ボリュームと、前記第2運用ボリュームのスナップショットの差分データを記憶する第2差分ボリュームと、前記差分データを管理する第2管理情報保持部と、前記第2ディスクサブシステムとの間でデータを転送する第2データ転送部と、が設けられるストレージシステムに用いられるリモートコピー方法であって;With the first procedure in which the first data transfer unit transmits the update data written to the first operation volume to the second data transfer unit;前記第1データ転送部が、前記第1運用ボリュームに書き込まれる更新データを前記第2データ転送部に送信する第1手順と;The second data transfer unit stores the update data in the second operation volume, and stores the difference data written in the update data storage position of the second operation volume in the second difference volume. With the second procedure of updating the second management information holding unit and then notifying the first data transfer unit of the completion of the data update;前記第2データ転送部が、前記更新データを前記第2運用ボリュームに格納し、前記第2運用ボリュームの前記更新データの格納位置に書き込まれている差分データを前記第2差分ボリュームに格納し、前記第2管理情報保持部を更新し、その後、データ更新の完了を前記第1データ転送部に通知する第2手順と;When the first data transfer unit receives the data update completion notification from the second data transfer unit, the update data is stored in the update position of the first operation volume, and the difference data is stored in the first difference volume. A remote copy method having a third step of storing in and updating the first management information holding unit. 前記第1データ転送部が、前記第2データ転送部からのデータ更新完了通知を受信すると、前記更新データを前記第1運用ボリュームの前記更新位置に格納し、前記差分データを前記第1差分ボリュームに格納し、前記第1管理情報保持部を更新する第3手順と、を有するリモートコピー方法。
19
In the first procedure, the first data transfer unit writes update data written to the first operating volume, an update position where the update data is written, and difference data written at the update position of the first operation volume. , And the management information indicating the storage position of the difference data is collectively transmitted to the second data transfer unit;前記第1手順は、前記第1データ転送部が、前記第1運用ボリュームに書き込まれる更新データ、前記更新データが書き込まれる更新位置、前記第1運用ボリュームの前記更新位置に書き込まれている差分データ、及び前記差分データの格納位置を示す管理情報を一まとめにして前記第2データ転送部に送信し;In the second procedure, the second data transfer unit compares the difference data transmitted from the first data transfer unit with the difference data stored in the update position of the second difference volume, and said that When both difference data match, the update data transmitted from the first data transfer unit is stored in the update position of the second operation volume, and the difference data transmitted from the first data transfer unit is stored. The management information stored in the second difference volume and transmitted from the first data transfer unit is compared with the management information generated based on the storage position of the difference data in the second difference volume. When the management information matches, the second management information holding unit is updated based on the management information transmitted from the first data transfer unit, and then the completion of the data update is notified to the first data transfer unit. The remote copy method according to claim 18 to be notified. 前記第2手順は、前記第2データ転送部が、前記第1データ転送部から送信された差分データと、前記第2差分ボリュームの前記更新位置に格納されている差分データとを比較し、前記両差分データが一致している場合に、前記第1データ転送部から送信された更新データを前記第2運用ボリュームの前記更新位置に格納し、前記第1データ転送部から送信された差分データを前記第2差分ボリュームに格納し、前記第1データ転送部から送信された管理情報と、前記差分データの第2差分ボリュームへの格納位置に基づいて生成された管理情報とを比較し、前記両管理情報が一致している場合に、前記第1データ転送部から送信された管理情報に基づいて前記第2管理情報保持部を更新し、その後、データ更新の完了を前記第1データ転送部に通知する請求項18に記載のリモートコピー方法。
20
In the first procedure, the first data transfer unit transmits the update data written to the first operating volume and the update position where the update data is written to the second data transfer unit;前記第1手順は、前記第1データ転送部が、前記第1運用ボリュームに書き込まれる更新データ、及び前記更新データが書き込まれる更新位置を前記第2データ転送部に送信し;In the second procedure, the second data transfer unit reads the difference data stored in the update position of the second operation volume, stores the difference data in the second difference volume, and transmits the difference data from the first data transfer unit. The updated data is stored in the update position of the second operation volume, the second management information holding unit is updated based on the storage position of the difference data in the second difference volume, and then the data update is completed. The remote copy method according to claim 18, wherein the first data transfer unit is notified of the above. 前記第2手順は、前記第2データ転送部が、前記第2運用ボリュームの前記更新位置に格納されている差分データを読み出して前記第2差分ボリュームに格納し、前記第1データ転送部から送信された更新データを前記第2運用ボリュームの前記更新位置に格納し、前記差分データの第2差分ボリュームへの格納位置に基づいて前記第2管理情報保持部を更新し、その後、データ更新の完了を前記第1データ転送部に通知する請求項18に記載のリモートコピー方法。

Independent claims16

85 paragraphs, as filed

The present invention relates to a storage system having a snapshot function, and more particularly to a technique for transferring snapshot data.

Data protection is one of the important roles of storage systems that store information in the information-oriented society. The most common method of data protection is a backup that stores a copy of the data on storage on a backup medium such as tape. Even if the data on the storage during operation is lost due to a failure, failure, or operation error, the backup can restore the data at the time of saving by restoring the data based on the backup. And the damage can be minimized.

However, with the increase in storage capacity, the time required for backup has become a problem. Furthermore, in applications where data is updated frequently, even if a backup is created once, the difference with the backup will increase immediately, and in the unlikely event that damage will increase, it is necessary to create backups frequently. It is becoming. In addition, there is a demand that regular backups can be easily referred to in case the file is lost due to an operation error or when the contents of the file are to be compared with the past state.

The snapshot function is attracting attention as a function that meets such applications. The snapshot function is a function that maintains the data image on the storage in operation at the moment when the snapshot is taken and makes it accessible by means other than the storage in operation. Snapshots minimize the backup time that was a problem with tape backup by making them available at the time of acquisition without waiting for the entire data on the storage to be copied.

In order to maintain this snapshot, there is a method of utilizing a storage storage area for storing the data at the time of snapshot (see, for example, Patent Document 1).

According to this, when a snapshot of an active volume is taken, when an unupdated block that occurs after that is updated, the old data of the block is copied to the storage storage area and a virtual volume that provides the snapshot is generated. To do. Reading from the virtual volume returns the block of the read address if it has been copied to the storage storage area. If there is no copy in the storage storage area, the operation volume has not been changed, so a block with the same address on the operation volume is returned.

According to this technology, the image of the operating volume at the time of snapshot acquisition is maintained with a smaller storage capacity compared to the case where all the data of the operating volume at the time of snapshot acquisition is stored in another volume. be able to.

In addition, for data migration stored in the storage system, extended data transfer function (XRC: Extended Remote Copy) or equal data transfer function (PPRC: Peer-) for data migration being accessed from a higher-level device (host). to-Peer Remote Copy) has been proposed by IBM (see, for example, Non-Patent Document 1).<patcit num="1"><text>U.S. Pat. No. 5,691552</text></patcit><nplcit num="1"><text>"Implementing ESS Copy Services on S / 390", IBM P.502.8.5 DASD migration</text></nplcit>

The snapshot described above is realized by the primary volume, the differential volume and the mapping table. However, when migrating snapshot data, it was not considered to copy the three in sync. Therefore, for example, if there is a time lag between the primary volume, the difference volume, and the copy of the mapping table, the snapshot data will not be consistent during that time, and there will be a problem that the image (virtual volume) at the time of snapshot creation cannot be configured. Furthermore, if the data transfer function fails when the primary volume and the differential volume are copied and the mapping table is not copied, there arises a problem that the virtual volume of the snapshot cannot be configured. An object of the present invention is to provide a storage system capable of safely copying snapshot data.

The present invention comprises a first disk subsystem having a disk drive that is used for normal operation, a second disk subsystem that has a disk drive that stores a copy of data stored in the first disk subsystem, and the first disk subsystem. A communication line for connecting one disk subsystem and the second disk subsystem is provided, and the first disk subsystem includes a first operating volume for normal reading and writing and the first operating volume. The first difference volume that stores the difference data of the snapshot, the first management information holding unit that manages the difference data, and the first data transfer unit that transfers the data between the second disk subsystem are The second disk subsystem is provided with a second differential that stores a copy of the data stored in the first operational volume and a second differential that stores the difference data of the snapshot of the second operational volume. A storage system provided with a volume, a second management information holding unit that manages the difference data, and a second data transfer unit that transfers data between the second disk subsystem; The first data transfer unit transmits the update data written to the first operation volume to the second data transfer unit; the second data transfer unit stores the update data in the second operation volume. The difference data written in the storage position of the update data of the second operation volume is stored in the second difference volume, the second management information holding unit is updated, and then the completion of the data update is completed by the first. Notify the data transfer unit; When the first data transfer unit receives the data update completion notification from the second data transfer unit, the first data transfer unit stores the update data in the update position of the first operation volume, and the difference. The data is stored in the first difference volume, and the first management information holding unit is updated.

According to the present invention, the data of the snapshot can be kept consistent and the data star recovery can be enhanced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a storage system according to an embodiment of the present invention.

NAS (Network Attached Storage) 1 is connected to disk subsystem 2. NAS1 on the local side is connected to a client 7 that uses CIFS (Common Internet File System) and a client that uses NFS (Network File System) via network 6. Network 6 communicates using a protocol such as TCP / IP. It may be possible to communicate by Fiber Channel or iSCSI (internet SCSI). NAS1 is equipped with a file server (NEF / CIFS server unit), and provides a file sharing service to clients 6 and 7 by the file server.

In addition, NAS1 has a differential snapshot section. The difference snapshot unit creates and maintains snapshots and synthesizes virtual volumes by the difference snapshot creation program 122, the difference snapshot management program 123, and the difference snapshot synthesis program 124, which will be described later.

The disk subsystem 2 on the local side is provided with a plurality of disk drives. A logical unit (LU), which is a unit that the OS can recognize as a single disk, is set in the disk drive. Further, the disk drive constitutes a main volume group, and the main volume group includes a primary volume 201, a difference volume 202, and a mapping table 203.

In addition, the logical unit is composed of RAID (Redundant Array of Independent Disks), and the stored data has redundancy. Therefore, even if a part of the disk drive fails, the stored data is not lost.

The primary volume 201 is a volume used for normal operation, and is accessed by clients 7 and 8 to read and write data. The difference volume 202 stores the data stored in the primary volume 201 at the time of copy-on-writing of the snapshot. The mapping table 203 records the relationship between the primary volume 201 and the differential volume 202 for each generation of snapshots.

The disk subsystem 2 also has a remote copy section. The remote copy unit detects the changed part of the data stored in the main volume group and transfers the data to the remote disk subsystem 4, and the remote copy program 204 stored in the main volume group is executed. Realized by.

The remote side NAS 3 and the remote side disk subsystem 4 are provided on the remote side, and can provide the same functions as the local side NAS 1 and the local side disk subsystem 2.

The local side and the remote side are connected by the data transfer network 5. Network 5 is a data transferable connection between NAS1 on the local side and NAS3 on the remote side, and disk subsystem 2 on the local side and disk subsystem 4 on the remote side, and signals using the TCP / IP protocol. Send and receive data (data, control signals). The network 5 may be a SAN (Storage Area Network) that transmits / receives signals (data, control signals) by a Fiber Channel protocol that is more suitable for data transfer.

Data backup from the local side to the remote side may be performed between NAS or between disk subsystems. Although data backup between disk subsystems will be described in the following embodiments, the present invention may be applied to data backup between NAS.

Further, although the embodiment in which the NAS and the disk subsystem are separately provided on both the local side and the remote side has been described, the present invention can also be applied to a storage device in which the NAS and the disk subsystem are integrated.

FIG. 2 is a block diagram showing a configuration of NAS 1 according to an embodiment of the present invention.

NAS1 is provided with CPU 11, memory 12, network interface 14, and storage interface 15.

The network interface 14 sends and receives data and control signals to and from clients 6 and 7 using the TCP / IP protocol.

The storage interface 15 sends and receives data and control signals based on Fiber Channel to and from the disk subsystem 2.

The memory 12 is provided with a cache memory for temporarily storing data read / written to / from the disk. Further, the memory 12 stores a file server program 121, a differential snapshot creation program 122, a differential snapshot management program 123, a differential snapshot synthesis program 124, and a file system processing program 125, and the CPU 11 stores these programs. Various processes are performed by calling and executing.

The file server program 121 requests the file system processing program 125 to execute the read processing or the write processing of the file or the directory in response to the data access request from the clients 6 and 7, and the execution result is the request source. Return to clients 6 and 7.

Upon receiving the snapshot creation request, the snapshot creation program 122 creates a snapshot for the disk subsystem 2 primary volume. Specifically, the area of the mapping table 203 is set.

The difference snapshot management program 123 manages the difference volume 202 that stores the difference data necessary for maintaining the snapshot, writes data in response to the request of the file system processing program 125, and performs the process of maintaining the snapshot. Specifically, when writing data to the primary volume 201 using the mapping table 203, after copying the difference data stored in the primary volume 201 to the difference volume, the update data is written to the primary volume 201 and stored. Update the content.

The differential snapshot synthesis program 124 uses the primary volume 201 and the differential volume 202 to perform read processing of the virtual volume (that is, processing for making the snapshot available) in response to the request of the file system management program 125. Specifically, referring to the mapping table 203, it is determined whether to read the data from the primary volume 201 or the difference volume 202, the data is read from the determined volume, and the primary volume 201 is set when the snapshot creation request is made. Synthesize a virtual volume that provides the stored data.

The file system processing program 125 is the position of the volume storing the file or the directory and the block to be accessed in response to the read request and the write request of the file or the directory issued by the file server program 121 or the differential snapshot management program 123. And specify the size. In addition, the read processing and write processing of the virtual volume are issued to the snapshot synthesis program 124.

Next, snapshot management will be described. 3 and 4 are explanatory views of snapshot management according to the embodiment of the present invention.

When the snapshot creation program 122 receives the snapshot creation request, it registers the identification information of the new virtual volume in the mapping table 203 (Snapshot 1 difference volume storage position of the mapping table column in FIG. 3). At the time of creating the snapshot, the block of this virtual volume is associated with the block of the primary volume 201 on a one-to-one basis because the data storage position is not registered in the difference volume storage position column of the mapping table 203.

After that, when the data in the primary volume 201 is updated, the snapshot management program 123 copies the difference data before the update in the primary volume 201 to the difference volume 202, and after this copying, the update data is updated to the primary volume 201. Is written to update the storage contents of the primary volume 201. In copying the data from the primary volume 201 to the difference volume 202, the data may be actually moved or the pointer indicating the data storage location may be rewritten.

Further, the snapshot management program 124 sets the block in the virtual volume 202 corresponding to the block in the primary volume 201 whose data has been updated to the data stored in the primary volume 201 at the time of snapshot creation (that is, before the update). Update the mapping table 203 so that it corresponds to the block of the difference volume 202 in which the data) is stored.

For example, in FIG. 4, when the data stored in P1 of the primary volume is rewritten to "aaaaa" between the creation of snapshot 1 and the creation of snapshot 2, it is stored in P1 of the primary volume. After the difference data "AAAAA" is copied to D1 of the difference volume, the update data "aaaaa" is stored in P1 of the primary volume. At this time, the storage position D1 of the difference data is stored in the P1 column of the mapping table. Further, "1" indicating that the difference data is stored for snapshot 1 is stored in the upper first bit of the mapping table change presence / absence bitmap.

Also, when P2 of the primary volume is rewritten to "bbbbb" between the creation of snapshot 2 and the present time, the difference data "BBBBB" stored in P2 of the primary volume is copied to D2 of the difference volume. After that, the update data "bbbbb" is stored in P2 of the primary volume. At this time, the storage position D2 of the difference data is stored in the P2 column of the mapping table. At this time, D2 is stored not only in the difference volume storage position of snapshot 2 but also in the difference volume storage position of snapshot 1 that requires this difference data. Further, in the first bit and the second bit of the mapping table change presence / absence bitmap, "1" indicating that the difference data is stored for the snapshots 1 and 2 is stored (that is, change presence / absence). "11" is stored in the bitmap).

When the file system processing program 125 issues an access request to the virtual volume to the snapshot synthesizer 124, the snapshot synthesizer 124 refers to the mapping table and refers to the block or difference of the primary volume associated with the block of the virtual volume. Read data from a block of volume. Therefore, by accessing the virtual volume, the file system processing program 125 can use the information stored in the primary volume at the time when the snapshot creation request is issued, so that the file system snap to the clients 6 and 7 can be used. A shot image can be provided.

That is, the virtual volume is a virtual volume composed of storage areas in one or a plurality of disk devices, and is actually composed of a part of a block of the primary volume and a part of a block of the difference volume.

For example, in FIG. 4, the virtual volume corresponding to the primary volume at the time of creating snapshot 1 is "AAAAA" stored in D1 of the difference volume which is the difference data corresponding to P1, and the difference which is the difference data corresponding to P2. Each of "BBBBB" stored in D2 of the volume and "CCCCC" stored in P3 of the primary volume (data is read from the primary volume because there is no difference data corresponding to P3) is read, and these data are read. Is synthesized.

FIG. 5 is a flowchart of the data transfer process according to the first embodiment of the present invention.

First, when the data transfer unit on the local side detects a data update request by the differential snapshot management program 123 (that is, a copy-on-write occurs based on the update request) (S101), it analyzes the update request and turns it into an update request. Extract the included update data (data written to disk) and data update position (address to write data) (S102). After that, the difference data (data before update) stored in the update position of the primary volume 201 is read (S103). Further, the area of the difference volume for storing the difference data is determined, and the mapping information after the data is updated (the information of the area for storing the difference data written at the update position of the mapping table) is created (S104). At this stage, the mapping information is not written in the mapping table 203.

Then, the acquired update data, update position, difference data, and mapping information are grouped together and included in the request, and this request is transmitted to the remote disk subsystem 4 (S105).

The data transfer unit on the remote side monitors the arrival of the request (S106). When the data transfer unit on the remote side receives a request from the disk subsystem 2 on the local side, it extracts update data, update position, difference data, and mapping information from the received request (S107 to S110).

Then, the update data extracted from the request is written to the update position of the primary volume 401 (S111), and the difference data extracted from the request is written to the difference volume 402 (S112). The writing position of this difference data is a storage area of the difference data included in the mapping information extracted from the request. Then, the mapping information extracted from the request is written to the mapping table 403 (S113). After that, since the update of the data on the remote side is completed, a completion notification is sent to the local disk subsystem 2 (S114).

The data transfer unit on the local side that sent the request monitors the arrival of the completion notification (S115). Then, when the data transfer unit on the local side receives the completion notification from the remote disk subsystem 4, the update data is written to the primary volume 201 (S116), and the difference data read in S103 is written to the difference volume 202 (S117). , Write the mapping information created in S104 to the mapping table (S118).

As described above, in the data transfer process of the first embodiment, the update data, the difference data, and the mapping information required for the difference snapshot are grouped and transmitted from the local side disk subsystem 2 to the remote side disk subsystem 4. Therefore, even if a failure occurs during data transfer from the local side to the remote side, inconsistency in the snapshot data can be avoided.

FIG. 6 is a flowchart of the data transfer process according to the second embodiment of the present invention. In the data transfer process of the second embodiment, the data transferred from the local side to the remote side is the minimum necessary, and the transfer performance is emphasized.

The data transfer unit on the remote side monitors the arrival of the request (S124). When the data transfer unit on the remote side receives the request from the disk subsystem 2 on the local side, the update data and the update position are extracted from the received request (S125, S126).

Then, the difference data stored in the update position (update position extracted from the request) of the primary volume 401 is read (S127). Then, the area for writing the difference data is secured in the difference volume 402 (S128), and the difference data read in S127 is written in the area of the difference volume 402 secured in S128 (S129). After that, the update data extracted from the request is written to the update position extracted from the request (S130), and the area where the difference data is stored is written to the update position of the mapping table (S131). After that, since the update of the data on the remote side is completed, a completion notification is sent to the local disk subsystem 2 (S132).

The local data transfer unit that sent the request monitors the arrival of the completion notification (S133). Then, when the data transfer unit on the local side receives the completion notification from the remote disk subsystem 4, the difference data stored in the update position of the primary volume 201 is read and the update data is written in the update position (S134). .. Then, the difference data read from the update position is stored in the difference volume 202 (S135), and the area in which the difference data is stored is written in the update position of the mapping table (S136).

As described above, in the data transfer process of the second embodiment, the data transferred from the local side to the remote side is limited to the update data and the storage position, and other information necessary for copy-on-write (difference data, mapping table). Information) is acquired on the remote side. Therefore, the data transferred from the local side to the remote side can be suppressed to the minimum necessary, the time required for the transfer process can be shortened, and the transfer performance can be improved. In addition, it is possible to reduce the increase in the load on the data transfer network 5.

FIG. 7 is a flowchart of the data transfer process according to the third embodiment of the present invention. In the data transfer process of the third embodiment, the data is updated after confirming the match of the difference data and the mapping table to improve the reliability of data synchronization.

First, when the data transfer unit on the local side detects a data update request by the differential snapshot management program 123 (that is, the occurrence of copy-on-write based on the update request) (S141), it analyzes the update request and turns it into an update request. Extract the included update data (data written to disk) and data update position (address to write data) (S142). After that, the difference data (data before update) stored in the update position of the primary volume 201 is read (S143). Further, the area of the difference volume for storing the difference data is determined, and the mapping information after the update (information of the area for storing the difference data written at the update position of the mapping table) is created (S104). At this stage, the mapping information is not written in the mapping table 203.

The data transfer unit on the remote side monitors the arrival of the request (S146). When the data transfer unit on the remote side receives a request from the disk subsystem 2 on the local side, it extracts update data, update position, difference data, and mapping information from the received request (S147 to S150).

Then, it is determined whether or not the data stored in the update position of the primary volume 401 is equal to the difference data extracted from the request (S151). As a result, if both data are not equal, it is determined that the transferred data is abnormal, and an error is notified to the administrator (S162). On the other hand, if both data are equal, it is determined that there is no abnormality in the transferred data, and the update data extracted from the request is written to the update position of the primary volume 401 (S152).

Then, the difference data extracted from the request is written to the difference volume 402 (S153). The writing position of this difference data is a storage area of the difference data included in the mapping information extracted from the request. After that, the updated mapping information (information in the area for storing the difference data written in the update position of the mapping table) is created (S154).

Then, it is determined whether or not the mapping information created in S154 and the mapping information extracted from the request match (S155). As a result, if both mapping information do not match, it is determined that the transferred data is abnormal, and an error is notified to the administrator (S162). At this time, it is preferable to return the primary volume 401 and the difference volume 402 to the state before the data update by writing the difference data to the update position on the primary volume 401 and erasing the data written on the difference volume 402. ..

On the other hand, if both mapping information are equal, it is determined that there is no abnormality in the transferred data, and the mapping information extracted from the request is written in the mapping table 403 (S156). After that, since the update of the data on the remote side is completed, a completion notification is sent to the local disk subsystem 2 (S157).

The data transfer unit on the local side that sent the request monitors the arrival of the completion notification (S158). Then, when the data transfer unit on the local side receives the completion notification from the remote disk subsystem 4, the update data is written to the primary volume 201 (S159), and the difference data read in S143 is written to the difference volume 202 (S160). , Write the mapping information created in S144 to the mapping table (S161).

As described above, in the data transfer process of the third embodiment, the update data, the storage position of the update data, the difference data and the mapping information are transferred from the local side to the remote side, and the difference data on the local side and the difference on the remote side are transferred. Make sure that the data matches and write the update data. Furthermore, the mapping table is updated after confirming that the mapping information created on the local side and the mapping information created on the remote side match. Therefore, in addition to the effect of the first embodiment, the reliability of data transfer can be further improved.

8, 9, and 10 are flowcharts of data transfer processing according to the fourth embodiment of the present invention. In the data transfer process of the fourth embodiment, unlike the processes of the other embodiments described above, the data transfer method is changed depending on the degree of congestion of the data transfer network 5.

FIG. 8 is a flowchart of the transfer process of the local disk subsystem.

First, when the data transfer unit on the local side detects a data update request by the differential snapshot management program 123 (that is, the occurrence of copy-on-write based on the update request) (S171), it analyzes the update request and turns it into an update request. Extract the included update data (data written to disk) and data update position (address to write data) (S172). After that, the difference data (data before update) stored in the update position of the primary volume 201 is read (S173). Further, the area of the difference volume for storing the difference data is determined, and the mapping information after the data is updated (the information of the area for storing the difference data written at the update position of the mapping table) is created (S174). At this stage, the mapping information is not written in the mapping table 203.

After that, the data transfer unit on the local side monitors the utilization rate of the data transfer network 5 and calculates this utilization rate (S175). This utilization rate can be calculated, for example, by dividing the amount of data transmitted in the past hour by the line speed per hour (the amount of data that can be transferred).

Then, the calculated utilization rate is compared with the preset upper limit value (S176). As a result, if the network utilization rate exceeds the upper limit, it is determined that the load on the data transfer network 5 is large. Then, the acquired update data and the update position are included in the request, and the request is transmitted to the reception process 1 of the remote disk subsystem 4 (S177).

On the other hand, if the network utilization rate does not exceed the upper limit, it is judged that the load of the data transfer network 5 is small (there is still room), and the acquired update data, update position, difference data, and mapping information are grouped. Collectively include it in the request and send the request to the reception process 2 of the remote disk subsystem 4 (S178).

The local data transfer unit that sent the request monitors the arrival of the completion notification (S179). Then, when the data transfer unit on the local side receives the completion notification from the remote disk subsystem 4, the update data is written to the primary volume 201 (S180), and the difference data read in S173 is written to the difference volume 202 (S181). , Write the mapping information created in S174 to the mapping table (S182).

FIG. 9 is a flowchart of the reception process 1 of the remote disk subsystem.

The data transfer unit on the remote side monitors the arrival of the request (S191). When the data transfer unit on the remote side receives a request for reception process 1 from the disk subsystem 2 on the local side, the update data and the update position are extracted from the received request (S192, S193).

Then, the difference data stored in the update position (update position extracted from the request) of the primary volume 401 is read (S194). Then, the area for writing the difference data is secured in the difference volume 402 (S195), and the difference data read in S194 is written in the area of the difference volume 402 secured in S195 (S196). After that, the update data extracted from the request is written to the update position extracted from the request (S197), and the area where the difference data is stored is written to the update position of the mapping table (S198). After that, since the update of the data on the remote side is completed, a completion notification is sent to the local disk subsystem 2 (S199).

FIG. 10 is a flowchart of the reception process 1 of the remote disk subsystem.

The data transfer unit on the remote side monitors the arrival of the request (S201). When the data transfer unit on the remote side receives a request for reception process 2 from the disk subsystem 2 on the local side, update data, update position, difference data, and mapping information are extracted from the received request (S202 to S205).

Then, it is determined whether or not the data stored in the update position of the primary volume 401 is equal to the difference data extracted from the request (S206). As a result, if both data are not equal, it is determined that the transferred data is abnormal, and an error is notified to the administrator (S213). On the other hand, if both data are equal, it is determined that there is no abnormality in the transferred data, and the update data extracted from the request is written to the update position of the primary volume 401 (S207).

Then, the difference data extracted from the request is written to the difference volume 402 (S208). The writing position of this difference data is a storage area of the difference data included in the mapping information extracted from the request. After that, the updated mapping information (information in the area for storing the difference data written in the update position of the mapping table) is created (S209).

Then, it is determined whether or not the mapping information created in S209 matches the mapping information extracted from the request (S210). As a result, if both mapping information do not match, it is determined that the transferred data is abnormal, and an error is notified to the administrator (S213). At this time, it is preferable to return the primary volume 401 and the difference volume 402 to the state before the data update by writing the difference data to the update position on the primary volume 401 and erasing the data written on the difference volume 402. ..

On the other hand, if both mapping information are equal, it is determined that there is no abnormality in the transferred data, and the mapping information extracted from the request is written in the mapping table 403 (S211). After that, since the update of the data on the remote side is completed, a completion notification is sent to the local disk subsystem 2 (S212).

As described above, in the data transfer process of the fourth embodiment, the data transferred from the local side to the remote side according to the load status (line utilization rate) of the data transfer network 5 connecting the local side and the remote side. To change. That is, when the line is congested, the amount of transferred data can be reduced, and when the line is free, redundant data related to copy-on-write can be added to ensure reliability.

<figref num="1">It is a block diagram which shows the structure of the storage system of embodiment of this invention.</figref><figref num="2">It is a block diagram which shows the structure of NAS1 of embodiment of this invention.</figref><figref num="3">It is explanatory drawing of the management of the snapshot of the Embodiment of this invention.</figref><figref num="4">It is explanatory drawing of the management of the snapshot of the Embodiment of this invention.</figref><figref num="5">It is a flowchart of the data transfer process of 1st Embodiment of this invention.</figref><figref num="6">It is a flowchart of the data transfer process of the 2nd Embodiment of this invention.</figref><figref num="7">It is a flowchart of the data transfer process of the 3rd Embodiment of this invention.</figref><figref num="8">It is a flowchart of the transfer process on the local side in the data transfer process of the 4th Embodiment of this invention.</figref><figref num="9">It is a flowchart of the reception process 1 on the remote side in the data transfer process of the 4th embodiment of the present invention.</figref><figref num="10">It is a flowchart of the reception process 2 on the remote side of the data transfer process of the 4th embodiment of the present invention.</figref>

Code description

1 Local NAS 2 Local Disk Subsystem 3 Remote NAS 4 Remote Disk Subsystem 5 Data Transfer Network 6 LAN 7 CIFS Client 8 NFS Client 11 CPU 12 Memory 14 Network Interface 15 Storage Interface 121 File Server Program 122 Differential Snap Shot Creation Program 123 Difference Snapshot Management Program 124 Difference Snapshot Synthesis Program 125 File System Processing Program 201, 401 Primary Volume 202, 402 Difference Volume 203, 403 Mapping Table

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2004103821	Japan	A	2004-03-31
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Storage system, storage device and remote copy method

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