Apparatus and method for multiple generation remote backup and fast restore

Description: TECHNICAL FIELD [Detailed description of the invention]

[Technical field to which the invention belongs]

The present invention generally relates to remote backup techniques, and in particular to techniques that enable multi-generational remote backups and fast restores. However, it is not limited to that.

[Conventional technology]

Normally, in a remote backup system, it is possible to multiplex generate backup data (snapshot images) that are mirrored (stored) at a secondary site and that exist in a geographical area different from the primary site from the data at the primary site. The effect of remote backup is that you do not lose customer data in the event of a disaster that destroys the data stored on the primary site. Disasters are man-made such as power failure and fire; natural disasters such as earthquakes, volcanic eruptions and typhoons; political disasters such as rebellion and terrorism; or combinations thereof. By keeping the backup data in a remote location, the backup data of the site that is not affected by the disaster can be used, and the customer can escape from the disaster. For example, suppose your primary site is in California, which is occasionally hit by earthquakes. In this case, the customer can install the remote backup in a state away from California that is less affected by the earthquake. In this case, even if the data at the primary site is destroyed by the earthquake, the customer's processing can be continued by restoring the backup data at the secondary site at a remote location.

[Problems to be Solved by the Invention]

However, there is usually a considerable distance between the primary and secondary sites, and it takes a considerable amount of time to recover lost data from the secondary site. For example, even if the primary and secondary sites are connected through a SAN join, the SAN is slower than the local connection. Therefore, if a large amount of data is lost in a disaster, it can take several hours or more to recover the data. Therefore, there is a need for new technology that enables fast data recovery.

[Means for solving problems]

The present invention provides a system and technique for generating multi-generational remote backups and enabling high-speed restore. In one embodiment of the invention, in a network, a local host is communicated to a primary storage device at a local storage location, and a remote secondary storage device is communicatively coupled to a primary storage device. In addition, the coupling includes multiple volumes that store snapshots of each primary and secondary storage device at each of the local and remote locations. In one embodiment of the invention, there is a control manager engine that couples to both the primary and secondary storage devices. The engine resides in the same location as the primary or secondary storage device, or in a third location. This engine creates a backup of the primary storage in the secondary storage. After making a backup of the primary storage, the engine creates snapshot backups of both the primary and secondary devices, resulting in exactly the same snapshot backup. One snapshot backup is stored on the snapshot volume in the same location as the primary storage, and the other snapshot backup is stored on the snapshot volume in the same location as the secondary storage. In addition, multi-generational snapshot backups are generated as well during operation. In order to recover the lost data of the primary storage caused by a disaster or the like, the user specifies which generation of snapshot backup to use. When the generation specification is complete, the engine determines if the snapshot of the specified generation is stored locally and is available. If a locally stored snapshot is available, use that snapshot to recover the primary storage, which is a regular remote snapshot. Faster restore is possible than using a chat. If not available, use the remote snapshot to recover the primary storage. As a result, the engine first attempts to use local snapshots, which can be expected to have faster restores than using remote backups. This is because recovery from the local volume enables faster data transfer than the remote volume. The backup techniques in the present invention can be summarized as follows: Backup the primary storage device to a secondary storage device that resides at a remote site; Make a snapshot backup of the secondary storage device at the remote site; Make a snapshot backup of the primary storage device to the local site Make; Make a snapshot backup of the secondary storage device at a remote site; Repeat the above operations throughout operation to generate snapshots of different generations, and for each generation, the same snapshots will be local to each other. Make sure it exists at each remote site.

BEST MODE FOR CARRYING OUT THE INVENTION

The following description will be based on one application and requirement so that anyone with knowledge in the art can carry out and use the present invention. Anyone familiar with the art can reveal a variety of modifications, and based on the principles set forth herein, without leaving the spirit and scope of the present invention, other embodiments, It can be applied to applications. Therefore, the present invention is not limited to the examples shown herein, but must be construed most broadly to the extent that the principles, features, and techniques disclosed herein are consistent. FIG. 1 is a block diagram illustrating a network coupling 100 according to an embodiment of the present invention. The network coupling 100 includes a local host 110 communication-coupled to a network 105 such as the Internet and a local storage 120. Further, the network coupling 100 includes a remote host 115 communication-coupled to the network 105 and the remote storage 150. In this embodiment, the remote storage 150 is directly connected to the local storage 120 so that it can communicate with the local storage 120 through the network coupling 145. The local storage 120 includes a primary storage device 125 for storing data generated and used by the local host 110. The remote storage 150 includes a secondary storage device 155 for storing backups of the primary storage device 125. The local storage 120 and the remote storage 150 include additional devices (volumes) for storing snapshots of the primary storage device 125 and the secondary storage device 155, respectively. Local snapshot volume 1 (L / S1) 130 ~ N (L / SN) 140 at the local site and remote snapshot volume 1 (R / S1) 160 ~ N (R / SN) 170 at the remote site correspond to this. .. The remote host 115, described in more detail in connection with FIG. 2, is a local storage 120, a remote storage 150, or another third location. May be present in. The remote host 115 has a control manager engine 200 (Figure 2). The engine 200 backs up (synchronizes) data from the primary storage device 125 to the secondary storage device 155, as discussed below. In addition, the Engine 200 forms a multi-generational snapshot backup of the primary storage device 125 and the secondary storage device 155 throughout operation. For example, L / S₁ 130, L / S₂ 135, L / S_N Each 140 holds a different generation of snapshots, corresponding to each time point and other variables of the primary storage device 125. Similarly, R / S₁ 160 holds a snapshot of secondary storage device 155, the contents of which are L / S₁ Exactly the same as 130. Similarly, R / S₂ 165 to R / S_N L / S up to 170₂ 135 to L / S_N Same as up to 140. In one embodiment, the primary storage device 125 is communicatively coupled to the secondary storage device 155 through a SAN (Storage Area Network), local SAN, global SAN, remote local SAN, or multiple SANs (not shown). .. Similarly, localhost 110 is joined to remote host 115 through one or more SANs. Further, the network coupling 100 may have an additional host and storage device. Figure 2 is a block diagram illustrating the remote host in Figure 1. The remote host 115 is a control manager engine 200 and a TOC (Table of). Content) has 210. The Control Manager Engine 200 performs backup and restore operations using the TOC210, which retains the location and time of the snapshot backup. In this example, TOC210 is referred to as a table, but it is clear to anyone with a normal knowledge of the field that it may have any data structure. The TOC210 is described in more detail in connection with FIG. The Control Manager Engine 200 first backs up the primary storage device 125 by synchronizing the data in the primary storage device 125 to the secondary storage device 155; the snapshots of the primary storage device 125 and the secondary storage device 155 are exactly the same. Simultaneously create a snapshot of the primary storage device 125 and the secondary storage device 155 so that the snapshot of the primary storage device 125 is stored in the local location and the snapshot of the secondary storage device 155 is stored in the remote location; And update TOC210. In the present invention, the engine 200 produces a multi-generational snapshot, i.e., a point-in-time snapshot, to allow later restore at a specified point in time. If there are already multi-generational snapshots at local and remote sites, Engine 200 will store the newly generated snapshots on the volume containing the oldest snapshots, thereby replacing the oldest snapshots. .. Alternatively, the engine 200 may allow the user to specify a volume (ie, an erased volume) to store the newly generated snapshot. To restore data, the user first specifies the snapshot generation to use to restore the data. Alternatively, as another embodiment, the engine 200 may automatically select, for example, the latest generation, which is preconfigured to be used to recover data. Engine 200 then breaks the coupling 145 between the primary storage device 125 and the secondary storage 155; determines if the specified snapshot generation is locally stored and available; the specified snapshot generation Is stored locally and, if available, restores data to the primary storage device 125 using the snapshot volume; If the snapshot of the selected generation is not stored locally, restore from the remote snapshot of that generation to the secondary storage device 155, then recover the join 145 and data from the secondary storage device 155 to the primary storage device 125. To restore. Figure 3 shows a block diagram of the TOC210 of remote host 115 (Figure 1). The TOC210 has two data structures 300 and 310, respectively, corresponding to the primary storage device 125 and the secondary storage device 155. In one embodiment, the data structure 300 corresponds to each pair of primary storage device 125 and local snapshot, with the pair name (ie, primary storage device 125 and secondary storage device) at the time the backup was generated. 155 pair name); pair group name; primary volume identifier; local snapshot volume identifier; has data such as backup start and end times. The data structure 310 corresponds to each pair of primary storage device 125 and local snapshot at the time the backup was generated, eg, the pair name (ie, the pair name of primary storage device 125 and secondary storage device 155); Pair group name; Secondary volume identifier; Remote snapshot volume identifier; It has data such as backup start and end times. FIG. 4 is a flowchart illustrating the backup method 400 according to the embodiment of the present invention. First, engine 200 temporarily suspends the mirroring process between the primary storage device 125 and the secondary storage device 155 (that is, suspends the transfer of new copies from the primary storage device 125 to the secondary storage device 155). Suppress the transfer of new data between storage device 125 and secondary storage device 155 (step 410). In addition, the engine 200 has a primary storage device 125 and (L / S).₁ 130-L / S_N Suspend the mirror between the selected local snapshot volumes (such as 140) to prevent the generation of new snapshots (step 410). Furthermore, once the mirror between the primary storage device 125 and the working local snapshot volume is interrupted, the working local snapshot volume will have the same copy (ie, snapshot) as the primary storage device 125. However, if this was the first backup, then the backup for primary storage device 125 does not exist for either secondary storage device 155 or the local snapshot volume. Therefore, for the first backup (as evidenced by the empty TOC210), both the local and remote snapshot volumes are mirrored. The engine 200 then determines whether the secondary storage device 155 is in the determined state (ie, there are no untransferred copies from the primary storage device 125) (step 420). If it is in the unconfirmed state, wait for the secondary storage device 155 to be in the confirmed state. When the secondary storage device 155 is confirmed, the engine 200 temporarily selects the secondary storage device 155 and the selected remote snapshot volume, R / S.₁ 160-R / S_N Break the bond with 170 (step 430) to prevent new snapshots from being generated. When the secondary storage device 155 is in the confirmed state, the secondary storage device 155 will have the same copy as the primary storage device 125. In addition, once the selected remote snapshot volume and the secondary storage device 155 are interrupted, the remote snapshot volume mirrored by the secondary storage device 155 is the same copy (ie, snap) as the primary storage device 125. You will have a shot). In the embodiment, the volume of the snapshot used by the user can be specified. In another embodiment, that is, if not specified by the user, the engine 200 can save the snapshot to the volume with the oldest snapshot, which erases the oldest snapshot. After suspending the mirroring process between the secondary storage device 155 and the remote snapshot volume (step 430), engine 200 updates the TOC210 with the backup result (ie the volume identifier where the snapshot was saved and at the start and end of the backup). After reflecting (step 440), this process is completed. After updating the TOC210, engine 200 restores mirror operation between the primary storage device 125 and the secondary storage device 155. As another method of the present invention, the mirror operation between the primary storage device 125 and the secondary storage device 155 is continuously interrupted, and the secondary storage device 155 has a previous backup of the primary storage device 125. The engine 200 takes a snapshot of the secondary storage device 155 and flashes out the data stored in that device. The engine 200 then restores the mirror operation between the primary storage device 125 and the secondary storage device 155, interrupts the mirror between them again (step 410), and is the secondary storage device 155 in a confirmed state? Judge whether or not. When the secondary storage device 155 is in a confirmed state, engine 200 updates the TOC210, including the update record for the secondary storage device (step 440). FIG. 5 is a flowchart 500 illustrating a restoration method according to the present invention. For example, in order to restore the data of the primary storage device 125 after a disaster, etc., the snapshot generation to be used must be decided (step 510). In the embodiment, the engine 200 uses a preselected snapshot, such as the latest generation snapshot. Engine 200 checks to see if the coupling 145 between the primary storage device 125 and the secondary storage device 155 is interrupted (step 520) and, if not, interrupts it (step 530). When this coupling is interrupted, the engine 200 determines if the specified snapshot exists in the local storage 120 (step 540) by checking the TOC210 that holds the location data for which the snapshot was generated. To do. If present, undamaged and usable, Engine 200 reverse-synchronizes the snapshot volume to primary storage device 125 (step 570) and primary storage device 1 Restore (recover) 25 data and exit. The engine 200 checks the TOC210 to determine which local snapshot volume holds which snapshot generation. If the local site snapshot is unavailable, reverse sync the secondary storage device 155 from the remote site snapshot volume that holds the specified generation of snapshots (step 550). The engine 200 checks the TOC210 to determine which remote snapshot volume holds which snapshot generation. The engine 200 then reverse-synchronizes from the secondary storage device 155 to the primary storage device 125 (step 560), restores the data in the primary storage device 125, and exits. What has been described so far is a preferred embodiment of the present invention. It goes without saying that changes and modifications are made without departing from the scope of the invention as defined in the claims. The present invention will be described with reference to the following drawings, but the present invention is not limited to this drawing, and is not limited thereto. Unless otherwise noted, the same elements are referred to by the same reference number throughout the drawing. Restore the data on the chair 125 and exit. What has been described so far is a preferred embodiment of the present invention. It goes without saying that changes and modifications are made without departing from the scope of the invention as defined in the claims. The present invention will be described with reference to the following drawings, but the present invention is not limited to this drawing, and is not limited thereto. Unless otherwise noted, the same elements are referred to by the same reference number throughout the drawing. Restore the data on the chair 125 and exit. What has been described so far is a preferred embodiment of the present invention. It goes without saying that changes and modifications are made without departing from the scope of the invention as defined in the claims. The present invention will be described with reference to the following drawings, but the present invention is not limited to this drawing, and is not limited thereto. Unless otherwise noted, the same elements are referred to by the same reference number throughout the drawing.

[Effect of the invention]

The restore technique of the present invention is as follows: Specify the generation of snapshots used to recover data to the primary storage device; determine if the snapshots of the specified generation exist and are available at the local site; Use this local snapshot to recover the primary storage if it is local and available; if the snapshot is not local, the remote site snapshot will recover the secondary storage device and the primary storage from this secondary storage device. Recover the device. Therefore, in the system and technology of the present invention, fast recovery is possible when local snapshots are available. Other effects are also described throughout this specification. Further properties and effects of the present invention can be understood from the rest of the specification and the drawings.

[Simple explanation of drawings]

[Figure 1]

FIG. 1 is a block diagram illustrating a network coupling according to an embodiment of the present invention.

[Figure 2]

Figure 2 is a block diagram illustrating the remote host in Figure 1.

[Fig. 3]

Figure 3 is a block diagram illustrating the table contents of the remote host in Figure 1.

[Fig. 4]

FIG. 4 is a flowchart illustrating a backup method according to an embodiment of the present invention.

[Fig. 5]

FIG. 5 is a flowchart illustrating a restoration method according to an embodiment of the present invention.

[Explanation of symbols]

105 Network, 110 Local host, 115 Remote host, 120 Local storage, 150 Remote storage, 200 Control manager engine