JP6939023B2 - Data management systems, storage devices, backup devices, methods and programs - Google Patents

Description

The present invention relates to a data management system for managing data stored in a storage device, a storage device, a backup device, a backup method of the storage device, and a backup program of the storage device.

As a method of backing up the data stored in the storage device, a method called differential backup is widely used in order to reduce the amount of data transferred to and from the storage device and the amount of data stored on the backup device side. The differential backup is a method of backing up only the difference from the timing of the previous backup when the backup device backs up.

In the differential backup, the backup device backs up (acquires and stores) all the data of the target storage device in the first time, and then in the second and subsequent times, after the previous backup in the target storage device. Back up only the updated part, that is, the differential data. When restoring data (returning to the state at the time of the past backup), the backup device shall sequentially apply the difference data from the second time to the specified backup time to the data acquired at the time of the first backup. Restores the data state at the specified point in time.

The backup device is usually provided outside the storage device in case of a failure that makes the storage device unusable.

When the backup device is provided outside the storage device, it is preferable that the backup device can identify the updated data without knowing the detailed internal structure of the storage device to be backed up.

For example, when the file system that controls the storage device manages the last modification date and time of each file, such as the file system of the NAS (Network Attached Storage) storage device, the difference data is specified by referring to them. can. For example, the backup device may compare its own last backup date and time with the last update date and time of each file, and determine whether or not each file needs to be backed up based on whether or not the last update date and time of the file is newer than the previous backup date and time. good. In this way, if the storage device has a file system that manages the modification date and time of the file, the difference data can be specified relatively easily. For example, the xcopy command, which is widely used for backing up Microsoft Windows®, is an example of backup software that executes such an algorithm.

However, many storage devices including a storage unit that manages a storage area in a predetermined block unit, such as a SAN (Storage Area Network) storage device, do not have a mechanism for managing the last update date and time. Therefore, for such a storage device, it is not possible to specify the difference data from the data blocks stored in the storage unit by using the last update date and time as described above.

Hereinafter, in the present invention, a storage device including one or more such storage units may be referred to as a “block storage device”. The storage unit in the block storage device may be a physical unit or a logical unit (LU). Further, in the following, each of the storage units included in the block storage device may be referred to as a block device.

As a method of realizing the differential backup for the block storage device, for example, the differential data can be specified by acquiring all the data each time and comparing it with the state at the time of the previous backup. However, this method requires reading of all data and checksum calculation, which not only imposes a load and time cost on the backup device side, but also imposes a load on the storage device side, resulting in deterioration of the performance of the storage device. There is a problem of being connected.

Further, as another method, there is a method in which the block storage device side is provided with a mechanism for recording the last update time in association with each block (see, for example, Patent Document 1).

Further, as another method, there is a method in which the backup device analyzes the updated part by referring to the internal data held by the block storage device for snapshot management and the like (see, for example, Patent Document 2). ..

Japanese Unexamined Patent Publication No. 2008-217209 Japanese Unexamined Patent Publication No. 2008-225615

However, the method described in Patent Document 1 has a problem that the time on the storage device side and the time on the backup device side must be strictly synchronized, and it is difficult to guarantee the consistency of the backup data. There is. For example, if you mistakenly determine that one updated block has not been updated due to a time lag between the two devices, the backup data will be inconsistent, but if you restore without knowing it. , The entire block device may become unavailable.

As a countermeasure, in order to allow the time difference, a method such as setting 10 minutes before the previous backup as the reference time can be considered, but how much the time difference depends on the storage device side. Therefore, it is difficult to obtain the optimum value, and if the amount of deviation is allowed to be large, there is a high possibility that the data of the block that has not been updated will be specified as the difference data. The load of memory capacity becomes large.

Further, in the method described in Patent Document 1, a new area for managing the last update time is required for the number of blocks on the block storage device side. Therefore, there is a problem that the memory usage on the storage device side increases as the number of blocks increases.

For example, assuming that the system is operated for 10 years and one year is 365 days without considering leap years and leap seconds, 10 years is 315,360,000 seconds. If an attempt is made to implement the last update time with a counter value that counts in units of 1 second, the number of seconds does not fit in 16 bits, and a data capacity of more bits is required. Considering the calculation efficiency, the last update date and time is managed by 32-bit data. For example, when a block device of 1 TiB is divided into blocks of 32 KiB units, if 32 bits of memory are required for each block, the control memory of the storage device consumes 31250 blocks × 32 bits = 1 MiB.

Further, in Patent Document 2, on the server device side connected to the block storage device, the number of accesses, the number of snapshots created, the number of mounts, the number of backups, the number of restores, etc. in the block storage device are acquired, and files are filed based on the acquisitions. It is stated that the transition of the group is judged. However, Patent Document 2 only describes that the server that has acquired these data makes a magnitude comparison with a specific variable as a method of determining migration, and discloses a specific logic for differential backup. Not.

In order to perform differential backup without inconsistency, it is necessary to know how these times are managed on the block storage side and how the processing that measures these times is performed. .. However, if it is necessary to control the differential backup based on the internal processing different for each storage device, there is a problem that the implementation of the backup device becomes complicated and the versatility is lost.

In view of the above-mentioned problems, the present invention is a data management system, a storage device, a backup device, and a storage device that can realize a differential backup of a block storage device with a simple logic and with a smaller processing load and / or a smaller resource load. It is an object of the present invention to provide a backup method of a storage device and a backup program of a storage device.

The data management system according to the present invention includes a storage device including one or more storage units that manage a storage area in a predetermined block unit, and a backup device that backs up the data stored in the storage unit of the storage device. When the storage device detects a quiesce point at a predetermined timing while the data stored in the storage unit is quiesce in the own device, the quiesce point that updates the value of the quiesce point counter held by the own device. When data is written to either the counter update unit or a block that is a plurality of data areas in block units owned by the storage unit, the last update period held by the own device in association with each block. The last update period update unit that updates the last update period corresponding to the block to the value of the quiesce point counter, and the quiesce point information providing unit that outputs the quiesce point counter and the last update period in response to a request from the backup device. When backing up, the backup device includes a quiesce point counter, a quiesce point information acquisition unit that acquires the last update period of the storage unit to be backed up, the acquired last update period, and itself. Based on the reference point counter that indicates the backup reference point for each of the blocks held by the device, the blocks that the storage unit targeted for backup has data updated since the last backup. It is characterized in that it includes an update block detection unit that detects the update block, and holds the acquired quiesce point counter as the update block and the reference point counter for the current backup of the specified block.

The storage device according to the present invention has one or more storage units that manage a storage area in a predetermined block unit, and a stationary point at a predetermined timing in a state where the data stored in the storage unit in the own device is stationary. When it is detected, when data is written to either the quiesce point counter update unit that updates the value of the quiesce point counter held by the own device or the block that is a plurality of data areas of the block unit of the storage unit. , The last update period update unit that updates the last update period corresponding to the block among the last update periods held by the own device corresponding to each block to the value of the quiesce counter, and the request from the backup device. It is characterized in that it is provided with a quiesce point counter and a quiesce point information providing unit that outputs the last update period according to the above.

The backup device according to the present invention can be used from a storage device to a storage device when backing up data stored in a storage unit of a storage device including one or more storage units that manage storage areas in predetermined block units. The quiesce point counter whose value is updated when a quiesce point at a predetermined timing is detected while the data stored in the storage unit is quiesce, and the last update period of the storage unit to be backed up. , When data is written to any of the blocks that are the data area of the storage unit, the last update period corresponding to the block is updated to the value of the quiesce counter , and the last update period is acquired. The storage unit to be backed up has a quiesce point information acquisition unit, an acquired last update period, and a reference point counter indicating a backup reference point for each of the blocks held by the own device. The update block, which is the block whose data has been updated since the last backup, is detected from the blocks, and the acquired quiesce point counter is retained as the reference point counter for the current backup of the block specified as the update block. It is characterized by having an update block detection unit.

In the backup method of the storage device according to the present invention, the storage device including one or more storage units that manage the storage area in a predetermined block unit is in a state where the data stored in the storage unit is stationary in the own device. When a quiesce point at a predetermined timing is detected, the value of the quiesce point counter held by the own device is updated, and the storage device for any of the blocks which are a plurality of data areas of the block unit of the storage unit. When the data is written, the last update period corresponding to the block among the last update periods held by the own device corresponding to each block is updated to the value of the quiesce point counter, and the storage device stores the data. In response to a request from the backup device that backs up the data stored in the unit, the quiesce point counter and the last update period are output, and when the backup device backs up, the quiesce point counter and the backup target are set. The last update period of the storage unit is acquired, and the backup device obtains the acquired last update period and the reference point counter indicating the backup reference point for each of the blocks held by the own device. From the blocks of the storage unit targeted for backup, the update block, which is the block whose data has been updated since the last backup, is detected, and the acquired quiesce point counter is the block specified as the update block this time. It is characterized in that it is held as a reference point counter for the backup of.

The backup program of the storage device according to the present invention stores data stored in the storage unit of the storage device including one or more storage units that manage the storage area in a predetermined block unit in the computer. A quiesce point counter whose value is updated when a quiesce point at a predetermined timing is detected from the device while the data stored in the storage unit is quiesce in the storage device, and a storage unit to be backed up. a last update period, when data is written to any of the data area of the storage unit block, in which the last update period corresponding to the block is updated to the value of the quiescent point counter, final The backup target is based on the quiesce point information acquisition process for acquiring the update period, the acquired last update period, and the reference point counter indicating the backup reference point for each of the blocks held by the own device. Among the blocks held by the stored storage unit, the update block, which is the block whose data has been updated since the last backup, is detected, and the acquired quiesce point counter is used as the update block for this backup of the block. It is characterized in that the update block detection process held as a reference point counter is executed.

According to the present invention, differential backup of a block storage device can be realized with simple logic and with less processing load and / or less resource load.

It is a block diagram which shows the structural example of the data management system of 1st Embodiment. It is a flowchart which shows an example of the operation of a block storage device 1. It is explanatory drawing which shows the example of the quiescent point counter 141 and the last update period 142 held in the meta information management unit 14. It is explanatory drawing which shows the example after the update of the last update period 142. It is a flowchart which shows an example of the operation of a block storage device 1. It is a flowchart which shows an example of the operation of a block storage device 1. It is explanatory drawing which shows the example after the update of the quiescent point counter 141. It is a flowchart which shows the example of the backup operation of the backup apparatus 2. It is a flowchart which shows the example of the backup operation of the backup apparatus 2. It is explanatory drawing which shows the example of the recorded contents of a backup file. It is a schematic block diagram which shows the structural example of the computer which concerns on embodiment of this invention. It is a block diagram which shows the outline of the data management system of this invention.

Embodiment 1.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of the data management system of the first embodiment. The data management system 500 shown in FIG. 1 includes a block storage device 1, a backup device 2, and an application device 3.

The block storage device 1 includes one or more storage units 11, a data input unit 12, a data output unit 13, a meta information management unit 14, a meta information providing unit 15, a last update period update unit 16, and a stationary unit. It includes a point detection unit 17, a stationary point counter update unit 18, and a snapshot storage unit 111.

As described above, the storage unit 11 is a storage means that manages its own storage area in predetermined block units. Each of the storage units 11 of the present embodiment has a plurality of data areas (hereinafter, simply referred to as blocks) in block units. Hereinafter, the data stored in the block may be referred to as block data.

The data input unit 12 receives a request for writing data to the storage unit 11 from the outside. The data output unit 13 receives a data read request from the storage unit from the outside.

The meta information management unit 14 manages (holds) the meta information of the block storage device 1. Examples of meta information include, but are not limited to, names, capacities, access privileges, and the like for each of the storage units 11.

The meta information management unit 14 of the present embodiment further holds a quiesce point counter 141 and a final update period 142 as meta information.

The quiescent point counter 141 is a counter whose value is updated (increased or decreased) every time a quiesce point is taken when the state of the block storage device 1 or the state of the storage unit 11 satisfies a predetermined condition. The quiescent point counter 141 is provided for each storage unit 11 when the quiescent point is independently set for each storage unit 11. The meta information management unit 14 may hold the quiescent point counter 141 in association with the identifier of the storage unit 11, for example.

The backup of many block storage devices has the characteristic of taking a quiesce point to ensure consistency. Also in this embodiment, the characteristic of taking such a stationary point can be utilized. The quiesce point of the present embodiment is not limited to the one taken to ensure consistency in the backup of the block storage device.

In the present embodiment, for example, a quiesce point is defined as a time point when the state of the block storage device 1 or the state of the storage unit 11 satisfies a predetermined condition. The predetermined condition includes a quiesced condition that the data is quiesced at least in the target (block storage device 1, storage unit 11, its group, etc.). In other words, the stationary point may be a time when the data is stationary in a predetermined target and a predetermined condition is satisfied. It is also possible to define the quiesce point as the time when a predetermined request (for example, a quiesce point securing request) from the backup device 2 is received. However, in the present embodiment, the quiescent points are assumed to occur at time intervals longer than at least 1 second.

In the present embodiment, the time point at which the block storage device 1 creates the snapshot will be described as an example of the quiesce point, but the quiesce point may be any time point satisfying the above conditions. Other examples of the quiesce point include, for example, the time when the application device 3 notifies that the file system is to be shut down, the time when the application device 3 unmounts the file system, and the like. The stationary point may be all of these states. That is, the predetermined conditions allow a plurality of different states.

Further, the final update period 142 is provided for each block of each storage unit 11. The meta information management unit 14 may hold the last update period 142 in association with, for example, the identifier of the storage unit 11 and the identifier of the block.

Here, the last update period 142 is the period during which the data was last updated in the corresponding block. More specifically, the last update period 142 is information of a predetermined time interval including the time when the data was last updated in the corresponding block.

In the present embodiment, such a last update period 142 is represented by using the quiescent point counter 141. More specifically, the last update period 142 indicates which interval of the time interval between two quiescent points adjacent in time that the time when the data was last updated in the corresponding block belongs. The information to be shown. The last update period 142 may be, for example, information (stationary point counter) indicating a stationary point corresponding to the start point of the period (the above time interval) in which the data was last updated in the corresponding block.

The meta information providing unit 15 provides the meta information held in the meta information management unit 14 to the outside.

The final update period update unit 16 updates the corresponding final update period 142 in response to a data writing request to the data input unit 12. Last update period The update unit 16 sets the last update period 142 associated with the request destination block to the value of the quiesce counter 141 corresponding to the block in response to a data write request to the data input unit 12, for example. Update. Here, the quiescent point counter 141 to which the block corresponds is, for example, the quiescent point counter 141 associated with the storage unit 11 having the block. When there is only one quiescent point counter 141, the only quiescent point counter 141 may be the quiescent point counter 141 corresponding to the block. When the quiescent point counter 141 is provided for each group of predetermined storage units 11, the quiescent point counter 141 associated with the group to which the storage unit 11 having the block belongs is quiesced by the block. The point counter 141 may be used. In the present embodiment, it is assumed that the relationship between the unit in which the quiescent point counter 141 is provided (that is, the quiesce point detection unit) and the block corresponding to the unit is known in the last update period update unit 16.

The quiescent point detection unit 17 detects that a quiesce point has been taken.

The quiescent point counter updating unit 18 updates the quiescent point counter 141 based on the detection result by the quiescent point detecting unit 17. The quiescent point counter updating unit 18 updates the corresponding quiescent point counter 141 each time it is detected by the quiescent point detecting unit 17 that a quiesce point has been taken. The quiescent point counter updating unit 18 updates the quiescent point counter 141 associated with the storage unit 11 of the detection source every time, for example, the quiescent point detecting unit 17 detects that a quiesce point has been taken. It is also assumed that the quiesce point counter update unit 18 also knows the relationship between the detected quiesce point and the quiesce point counter 141 of the update destination.

The snapshot storage unit 111 stores the snapshot.

Further, the backup device 2 includes a backup unit 21, a restore unit 22, a backup data storage unit 23, and a quiesce point counter storage unit 24.

The backup unit 21 backs up the data stored in each storage unit 11 of the block storage device 1 or the designated storage unit 11 (more specifically, the block data of each block included in the storage unit 11).

The restore unit 22 is the storage unit 11 of the block storage device 1 or the designated storage unit 11 based on the backup file described later and the information stored in the backup data storage unit 23, the quiesce point counter storage unit 24, and the like. Restore the data to.

The backup data storage unit 23 stores the backup data of each storage unit 11 included in the block storage device 1 to be backed up.

Further, the backup unit 21 includes a quiesce point securing unit 211 and an update block detection unit 212.

The quiesce point securing unit 211 secures a quiesce point to be backed up at the time of backup. The quiesce point securing unit 211 issues a predetermined event accompanied by the occurrence of a quiesce point to the block storage device 1 in a state where writing of data to at least the storage unit 11 to be backed up of the block storage device 1 is stopped. As a result, a stationary point may be secured. For example, when the quiesce point is at the time when the snapshot is updated, the quiesce point securing unit 211 causes the backup target to create a snapshot to generate the quiesce point. Further, the quiesce point securing unit 211 transmits, for example, when the quiesce point is the time when a predetermined request from the backup device 2 (for example, a quiesce point securing request) is received, the request for which the backup target is specified is transmitted. Generate a quiesce point.

When performing a new backup, the update block detection unit 212 detects a block whose data has been updated from the time of the previous backup of the backup target.

The quiesce point counter storage unit 24 holds a quiesce point counter 241 as a reference point for backup in association with each of the smallest units (for example, the storage unit 11) to be backed up. The quiescent point counter storage unit 24 may use the above as the quiesce point counter 241 in the initial state, and may further hold a quiesce point counter 241 associated with each of the acquired difference data 231 for each backup. The quiescent point counter 241 may be referred to as a "reference point counter" in the sense of indicating a backup reference point.

Here, in the quiesce point counter 241 held by the backup device 2, the quiesce point counter 141 corresponding to the target, which is acquired from the block storage device 1 at the time of backup immediately before the target, is set.

The application device 3 is a device that makes a data write request and a data read request to the block storage device 1 and inputs / outputs data to and from the block storage device 1.

In the present embodiment, the block storage device 1 may be a SAN storage device having an interface such as Fiber Channel, iSCSI, or SAS (Serial Attached SCSI). Further, the block storage device 1 may be, for example, a general-purpose server in which software for communicating with iSCSI or a unique protocol is installed. Further, the block storage device 1 may be, for example, a flash storage that communicates by NVM Express or a unique protocol.

Further, the backup device 2 is a general-purpose server in which, for example, software in which the backup unit 21 and the restore unit 22 are mounted is installed, and a storage device corresponding to the backup data storage unit 23 and the quiesce point counter storage unit 24 is provided. It may be. The backup device 2 may be a physical server or a virtual server. Further, the backup data storage unit 23 may be realized by an external storage connected to the backup device 2.

Further, the application device 3 may be an arbitrary server, a personal computer, or an information processing device such as a CPU provided in the personal computer. Further, the application device 3 may be, for example, a general-purpose server that creates a file system in the storage unit 11 of the block storage device 1 and stores a file of an application program or data in the file system. The application device 3 may be a physical server or a virtual server. Further, the application device 3 may be a sensor device such as a camera that records a still image or a moving image, for example.

Next, the operation of this embodiment will be described. First, the operation of the block storage device 1 side will be briefly described.

The block storage device 1 of the present embodiment divides each storage unit 11 into logical blocks of a certain size. For example, the size of each block may be 32 KiB. If the block is made smaller, the effect of reducing the amount of data by the differential backup in the backup device 2 is enhanced, but the memory usage is increased.

When the storage unit 11 is newly created, the block storage device 1 adds a quiesce point counter 141 corresponding to the new storage unit 11 and a last update period 142 to the meta information management unit 14, and initializes their values. To become. In this embodiment, the initial value of the quiescent point counter 141 is 1, and the initial value of the last update period 142 of each block is 0.

FIG. 2 is a flowchart showing an example of the operation of the block storage device 1 of the present embodiment. FIG. 2 is a flowchart showing an example of the operation of the block storage device 1 when receiving a data write request. In the example shown in FIG. 2, first, the data input unit 12 receives a data write request from the application device 3 (step S101).

Next, the data input unit 12 writes data to the block in response to the request (step S102). The block to which the data is written is not particularly limited.

When the data writing by the data input unit 12 is successful (Yes in step S103), the last update period update unit 16 updates the last update period 142 of the corresponding block (step S104). If the writing fails (No in step S103), the process proceeds to step S105 without performing step S104.

Finally, the data input unit 12 returns the writing result to the requester (step S105).

FIG. 3 is an explanatory diagram showing an example of a quiesce point counter 141 and a last update period 142 held in the meta information management unit 14. Note that FIG. 3A is an explanatory diagram showing an example of the quiescent point counter 141, and FIG. 3B is an explanatory diagram showing an example of the last update period 142.

In the block storage device 1, when the application device 3 requests the data input unit 12 to write and the writing is successful, the last update period update unit 16 updates the last update period 142 of the corresponding block.

FIG. 4 is an explanatory diagram showing an example after the update of the final update period 142. For example, in the initial state shown in FIG. 3, when the data in the block specified by the block number 3 is updated by writing, the final update period update unit 16 corresponds to the block as shown in FIG. The last update period 142 is set to 1, which is the value of the quiescent point counter 141.

Further, FIG. 5 is a flowchart showing an example of the operation of the block storage device 1 at the time of detecting a quiesce point. In the example shown in FIG. 5, first, the quiescent point detection unit 17 detects the quiescent point (step S111).

Next, the quiescent point counter update unit 18 updates the quiescent point counter 141 corresponding to the detected quiesce point (step S112).

Further, FIG. 6 is a flowchart showing an example of the operation of the block storage device 1 when receiving a snapshot request. In the example shown in FIG. 5, first, the block storage device 1 accepts the snapshot request (step S121).

Next, the snapshot function unit (not shown) of the block storage device 1 creates a snapshot of each storage unit 11 in response to the received snapshot request (step S122). As a result, the block data of each storage unit 11 is in a state where a stationary point is taken.

In the block storage device 1, after step S122 in which the quiescent point is taken, the operations of steps S111 to S112 are performed.

If the access to the block storage device 1 is frozen before taking the snapshot in step S122, unfilled data is written to the storage unit 11 before taking the snapshot. That is, the operations of steps S101 to S105 described above are performed.

For example, when the application device 3 creates a file system in the storage unit 11 of the block storage device 1, when the file system is frozen, a new write request to the file system is held and the storage unit 11 holds a new write request. Unwritten data is written, and the data in the storage unit 11 is in a state where a stationary point is taken. Then, when the freeze of the file system is released, the hold of the write request is released, and the data of the storage unit 11 is in a state where no quiesce point is taken. Many file systems have a file system freeze function.

FIG. 7 is an explanatory diagram showing an example after updating the quiescent point counter 141. By creating the above snapshot, the quiescent point counter 141 is updated to the state shown in FIG. 7, for example. In this example, an example is shown when there is no unfilled data in the storage unit 11, but when there is unfilled data, the final update corresponding to the block in which the data is written is shown. The period 142 is set to 1, which is the value of the quiescent point counter 141 at the time before taking the snapshot.

Next, the operation of the backup device 2 will be described. 8 to 9 are flowcharts showing an example of the backup operation of the backup device 2.

In the examples shown in FIGS. 8 to 9, first, the quiesce point securing unit 211 takes (secures) the quiesce point of the storage unit 11 to be backed up. The method of taking a quiesce point is, for example, shutting down the application device 3. Also, for example, unmounting the file system from the application device 3. Further, for example, the file system of the application device 3 is frozen, the block storage device 1 is made to create a snapshot of the storage unit 11, and the file system of the application device 3 is released from the freeze.

In this example, an example using the third method will be described. That is, a method of temporarily freezing the file system and creating a snapshot without shutting down the application device 3 and unmounting the file system will be described. It is possible to back up the file system without freezing it, but be aware that in that case, unwritten data may not be reflected and some files may not be restored.

First, the quiesce point securing unit 211 freezes data access to the block storage device 1 at the application level (step S201).

For example, the quiesce point securing unit 211 may log in to the application device 3 with Secure Shell and execute a command for freezing the file system.

Next, the quiesce point securing unit 211 causes the block storage device 1 to create a snapshot (step S202). For example, the quiesce point securing unit 211 may log in to the management interface of the block storage device 1 with Secure Shell and execute a command for creating a snapshot. Further, for example, the quiesce point securing unit 211 may execute a remote procedure call for creating a snapshot of the block storage device 1.

Next, the stationary point securing unit 211 releases the frozen state of the data access frozen in step S201 (step S203). While the file system is frozen, writing to the file system is suspended, so it is desirable to release the freeze as soon as possible.

If the application device 3 does not create a file system in the storage unit 11 of the block storage device 1, the above operation may be performed without going through the file system.

Next, the update block detection unit 212 makes a request to the meta information providing unit 15, and receives the quiesce point counter 141 and the final update period 142 (step S204). For example, the update block detection unit 212 may issue a SCSI command for requesting the block storage device 1 to read the meta information, and may receive data including the meta information from the block storage device 1 as a response. Further, for example, the update block detection unit 212 may log in to the management interface of the block storage device 1 with Secure Shell and execute a command to output meta information to obtain the information. Further, for example, the update block detection unit 212 may execute a remote procedure call for acquiring meta information of the block storage device 1 to obtain the information.

Next, the update block detection unit 212 saves the quiescent point counter 141 acquired in step S204 for this backup (step S205). The update block detection unit 212 may store the acquired quiescent point counter 141 as the quiescent point counter 241 in the quiescent point counter storage unit 24, for example.

The backup destination of the quiescent point counter 141 does not have to be, for example, the hard disk drive built in the backup device 2. The backup destination may be, for example, an external storage device connected to the backup device 2.

In this example, an example is shown in which one backup file is created for one backup in the quiesce counter storage unit 24 as a file system created in the hard disk drive built in the backup device 2. At this time, the update block detection unit 212 may determine the file name of the backup file from the identification ID of the storage unit 11 and the quiesce point counter 141. For example, when the identification ID of the storage unit 11 is 00114FB and the quiescent point counter 141 is 1, the file name of the backup file is, for example, 00114FB-00001. Let it be BAK. The update block detection unit 212 creates an empty file in the step.

Next, the update block detection unit 212 confirms whether the information regarding the previous backup (for example, the above backup file) exists (step S206), proceeds to step S207 if it does not exist, and proceeds to step S208 if it exists. move on.

In step S207, the update block detection unit 212 assigns 0 to the variable b indicating the backup reference point when the update block is obtained. This is the first backup because there is no information about the previous backup. In this example, in the first backup, only the blocks that have been written are backed up, and the blocks that are all zero, which is the initial state of the blocks without writing, are not backed up. By not backing up all zero blocks, the read process from the block storage device 1 can be omitted, and the capacity for storing data can be saved.

If the information regarding the previous backup exists, the update block detection unit 212 substitutes the quiescent point counter 241 at the time of the previous backup into the variable b (step S208).

Next, the processing of steps S210 to S212 is repeated for each target block of the snapshot stored in the snapshot storage unit 111 (loop L209).

That is, the update block detection unit 212 first substitutes the last update period of the target block acquired in step S204 into the variable a (step S210).

Next, the values of the variable a and the variable b are compared (step S211), and if a is large, the process proceeds to step S212, and if b is large or equal, step S212 is not executed and the loop L209 is continued.

On the other hand, if a is large, the target block is assumed to be an update block whose data has been updated since the previous backup, and the block data of the target block is backed up from the snapshot of the block storage device 1 (step S212). In this example, the block data of the update block is written to the backup file as the difference data.

FIG. 9 is an explanatory diagram showing an example of the recorded contents of the backup file. As an example of the contents to be added (recorded) to the backup file, as shown in FIG. 10, a set of a block number and a block data as an update block can be mentioned.

The update block detection unit 212 repeats loop L209, and when a is larger than b, adds a block number and a set of block data to the backup file.

When the loop L209 ends, the quiesce point securing unit 211 causes the block storage device 1 to delete the snapshot of the storage unit 11 as the backup target (step S213). When the block storage device 1 adopts the copy-on-write snapshot method, it is expected that the write performance of the storage unit 11 will be improved by deleting the snapshot created at the start of this backup. NS. However, deleting snapshots is not essential to the practice of the present invention. For example, in order to restore the snapshot data inside the block storage device 1 in a short time, the snapshot may be left without being deleted.

In order to restore the data backed up above, the restore unit 22 may read the oldest backup files in order and write them to the storage unit 11. Since the restore operation for restoring based on the differential backup data is widely known, detailed description thereof will be omitted.

As described above, the backup device 2 of the present embodiment can identify the updated block by a simple algorithm that compares the quiesce point counter at the time of the previous backup with the last update period of each newly acquired block. Therefore, the backup device 2 does not need to worry about other internal data of the block storage device 1 and the snapshot / replication function, and can implement the differential backup in a short period of time and at low cost.

Further, according to the present embodiment, it is not necessary for the backup device 2 to read all the data and compare it with the backup even at the time of the initial backup. Also, when backing up from a snapshot, the snapshot can be deleted after the backup is completed. Therefore, it is possible to improve the performance of the block storage device 1, prevent the increase in the data capacity of the backup device 2, and reduce the transfer load between the block storage device 1 and the backup device 2.

Further, as compared with the case of saving the last update date and time, it is not necessary to synchronize the time, and the memory usage on the block storage device 1 side can be reduced.

That is, when the block storage device 1 holds the last update date and time, it is considered that 32 bits are required per block when calculated from the general backup frequency and the product life, whereas the last update period 142 of the present invention. About 16 bits per block is sufficient.

In addition, users of the block storage device can back up in a short time, and a backup device with a low load at the time of backup can be obtained at low cost. By backing up outside the block storage device, it is backed up internally. It is possible to build a system that is less likely to lose data than taking a backup.

The number of bits in the last update period 142 was calculated under the following assumptions. That is, in general, many backups are taken during non-business hours and are often set daily at night or every weekend. In addition to this, even if backups are taken for irregular maintenance, it is considered sufficient to make backups several times a day. Also, considering the general maintenance period of storage products, it is considered sufficient if the numbers do not overflow for 20 years. According to the case assumed in this way, it suffices to support backups of 20 years x 365 days x 3 times = 219,000 times, and 16 bits (up to 65,535) is sufficient in consideration of processing efficiency. it is conceivable that.

In the modified example described later, 32 bits per block or 64 bits may be assumed in some cases, but it is more complicated than the method of comparing the last update time and the method of directly referring to the number of snapshots. There is no need for various controls or time synchronization, and the effects that can be realized only by an algorithm based on simple comparison and that data integrity can be guaranteed can still be obtained. That is, it is possible to reduce the processing load (the amount of data read is small) and / or the resource load (the amount of memory used is small) with simple logic.

Modification example.
It should be noted that at least some of the configurations and methods of the above embodiments can also be applied to incremental backups. In the case of incremental backup, the updated block may be detected by using the backup quiesce counter 241 which is the base point of the incremental backup instead of the quiesce counter 241 at the time of the previous backup.

Further, when the differential backup is performed only from the snapshot, the identification ID of the snapshot may be substituted as the quiesce point counter 141. For example, when the identification ID of the snapshot increases in the order of 1, 2, 3 ... Each time the snapshot is taken, the identification ID can be used as the quiesce point counter 141. In the present invention, the identification ID of such a snapshot is also regarded as one aspect of the quiescent point counter 141.

Further, the stationary point counter 141 may be a counter that increases (or decreases) at regular intervals. For example, the timer value that increases at 10-minute intervals may be set as the quiescent point counter 141. In that case, it is preferable that the process of updating the quiescent point counter 141 is performed in a state where data rewriting does not occur. Further, in that case, the backup device 2 backs up a block equal to the quiesce point counter 241 in addition to a block larger than the quiesce point counter 241 at the time of the previous backup. In the present invention, such a counter is also regarded as one aspect of the quiescent point counter 141.

Further, the quiescent point counter 141 may be a counter that increases (or decreases) with each fixed amount of writing. For example, the counter value that increases by 1 for every 32 MiB written may be set as the quiescent point counter 141. In that case as well, the backup device 2 backs up a block equal to the quiesce point counter 241 in addition to a block larger than the quiesce point counter 241 at the time of the previous backup. In the present invention, such a counter is also regarded as one aspect of the quiescent point counter 141.

Further, the quiescent point counter 141 may be a counter that increases (or decreases) with each writing. In the case of this example, a longer number of bits is required compared to using a counter that increases (or decreases) only when a quiesce point is taken, but the effect of realizing differential backup with a simple algorithm is obtained. Be done. In the present invention, such a counter is also regarded as one aspect of the quiescent point counter 141.

Next, a configuration example of the computer according to the embodiment of the present invention will be shown. FIG. 11 is a schematic block diagram showing a configuration example of a computer according to an embodiment of the present invention. The computer 1000 includes a CPU 1001, a main storage device 1002, an auxiliary storage device 1003, an interface 1004, a display device 1005, and an input device 1006.

The block storage device, backup device, and application device described above may be mounted on the computer 1000, for example. In that case, the operation of each device may be stored in the auxiliary storage device 1003 in the form of a program. The CPU 1001 reads a program from the auxiliary storage device 1003, deploys it to the main storage device 1002, and performs a predetermined process in the above embodiment according to the program.

Auxiliary storage 1003 is an example of a non-temporary tangible medium. Other examples of non-temporary tangible media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, etc. connected via interface 1004. Further, when this program is distributed to the computer 1000 by a communication line, the distributed computer may deploy the program to the main storage device 1002 and execute a predetermined process according to the above embodiment.

Further, the program may be for realizing a part of a predetermined process in each embodiment. Further, the program may be a difference program that realizes a predetermined process in the above embodiment in combination with another program already stored in the auxiliary storage device 1003.

Interface 1004 sends and receives information to and from other devices. In addition, the display device 1005 presents information to the user. Further, the input device 1006 accepts the input of information from the user.

Further, depending on the processing content in the embodiment, some elements of the computer 1000 may be omitted. For example, the display device 1005 can be omitted if the device does not present information to the user.

Further, a part or all of each component of each device is implemented by a general-purpose or dedicated circuit (Circuitry), a processor, or a combination thereof. These may be composed of a single chip or may be composed of a plurality of chips connected via a bus. Further, a part or all of each component of each device may be realized by a combination of the above-mentioned circuit or the like and a program.

When a part or all of each component of each device is realized by a plurality of information processing devices and circuits, the plurality of information processing devices and circuits may be centrally arranged or distributed. May be good. For example, the information processing device, the circuit, and the like may be realized as a form in which each is connected via a communication network, such as a client-and-server system and a cloud computing system.

Next, the outline of the data management system of the present invention will be described. FIG. 12 is a block diagram showing an outline of the data management system of the present invention. The data management system 600 shown in FIG. 12 includes a storage device 61 and a backup device 62.

The storage device 61 (for example, the block storage device 1) includes one or more storage units 611 that manage storage areas in predetermined block units, a quiesce point counter update unit 612, a final update period update unit 613, and a quiesce point. It is provided with an information providing unit 614.

When the stationary point counter updating unit 612 (for example, the stationary point counter updating unit 18) detects a stationary point at a predetermined timing in a state where the data stored in the storage unit is stationary in the own device, the own device holds the data. The value of the stationary point counter 615 is updated.

When data is written to any of the blocks which are a plurality of data areas of the block unit of the storage unit, the last update period update unit 613 (for example, the last update period update unit 16) associates the data with each of the blocks. Of the last update period 616 held by the own device, the last update period 616 corresponding to the block is updated to the value of the quiescent point counter 615.

The quiescent point information providing unit 614 (for example, the meta information providing unit 15) outputs the quiescent point counter 615 and the last update period 616 in response to a request from the backup device.

Further, the backup device 62 includes a quiesce point information acquisition unit 621 and an update block detection unit 622.

The quiesce point information acquisition unit 621 (a part of the update block detection unit 212) acquires the quiesce point counter 615 and the last update period 616 of the storage unit to be backed up when backing up.

Update block detection unit 622 (part of update block detection unit 212) Based on the acquired last update period 616 and the reference point counter 623 that indicates the backup reference point for each of the blocks held by the own device. , The update block, which is the block whose data has been updated since the last backup, is detected from the blocks of the storage unit to be backed up, and the acquired quiesce counter 615 is identified as the update block. It is held as a reference point counter 623 for this backup.

Although the present invention has been described above with reference to the present embodiment and examples, the present invention is not limited to the above embodiments and examples. Various changes that can be understood by those skilled in the art can be made within the scope of the present invention in terms of the structure and details of the present invention.

The present invention is suitably applicable to backup applications for storage units that store data on a block basis.

500 Data management system 1 Block storage device 11 Storage unit 111 Snapshot storage unit 12 Data input unit 13 Data output unit 14 Meta information management unit 141 Static point counter 142 Last update period 15 Meta information provider 16 Last update period Update unit 17 Static Point detection unit 18 Static point counter update unit 2 Backup device 21 Backup unit 211 Static point securing unit 212 Update block detection unit 22 Restore unit 23 Backup data storage unit 231 Difference data 24 Static point counter storage unit 241 Static point counter 3 Application device 1000 Computer 1001 CPU
1002 Main storage device 1003 Auxiliary storage device 1004 Interface 1005 Display device 1006 Input device 61 Storage device 611 Storage unit 612 Static point counter update unit 613 Last update period update unit 614 Static point information provider 615 Static point counter 616 Last update period 62 Backup Device 621 Stationary point information acquisition unit 622 Update block detection unit 623 Reference point counter

Claims (10)

A storage device including one or more storage units that manage a storage area in a predetermined block unit, and a backup device that backs up the data stored in the storage unit of the storage device.
The storage device is
When a quiesce point at a predetermined timing is detected in the state where the data stored in the storage unit is quiesce in the own device, a quiesce point counter update unit that updates the value of the quiesce point counter held by the own device is provided. ,
When data is written to any of the blocks that are a plurality of data areas of the block unit of the storage unit, the block is included in the last update period held by the own device in association with each of the blocks. The last update period update unit that updates the last update period corresponding to the value of the quiescent point counter, and
A quiesce point information providing unit that outputs the quiesce point counter and the last update period in response to a request from the backup device is included.
The backup device is
When performing the backup, the quiesce point counter, the quiesce point information acquisition unit that acquires the last update period of the storage unit to be backed up, and the quiesce point information acquisition unit.
Based on the acquired last update period and the reference point counter indicating the backup reference point for each of the blocks held by the own device, the previous block among the blocks held by the storage unit to be backed up is previously selected. Update block detection that detects the update block, which is the block whose data has been updated since the time of backup, and holds the acquired quiesce point counter as the reference point counter for the current backup of the block specified as the update block. A data management system characterized by including departments. The data management system according to claim 1, wherein the update block detection unit detects an update block by comparing the acquired last update period with the reference point counter. The backup device is
Claim 1 includes a quiesce point securing unit that issues a predetermined event accompanied by the occurrence of the quiesce point to the storage device in a state where writing of data to at least the storage unit to be backed up of the storage device is stopped. Alternatively, the data management system according to claim 2. The stationary point, when updating the snapshot, timing a predetermined time has elapsed, any one of the timing in which the write has been in a certain amount of writing timing or target memorize units in target memorize unit The data management system according to any one of claims 1 to 3, including the above. The data management system according to any one of claims 1 to 4, wherein the bit length of the static counter held by the storage device is 16 bits or less. In each of the storage units, each of the blocks is initialized with a predetermined value.
The stationary point counter is maintained for each memorize unit,
The data management system according to any one of claims 1 to 5, wherein the update block detection unit excludes blocks whose last update period has been acquired at the initial value from the backup target at the time of initial backup. One or more storage units that manage storage areas in predetermined block units,
When a quiesce point at a predetermined timing is detected in the state where the data stored in the storage unit is quiesce in the own device, a quiesce point counter update unit that updates the value of the quiesce point counter held by the own device is provided. ,
When data is written to any of the blocks that are a plurality of data areas of the block unit of the storage unit, the block is included in the last update period held by the own device in association with each of the blocks. The last update period update unit that updates the last update period corresponding to the value of the quiescent point counter, and
In response to a request from the backup device, the storage device being characterized in that a said stationary point counter and the last update period and still point information providing unit for outputting. When backing up the data stored in the storage unit of the storage device including one or more storage units that manage the storage area in a predetermined block unit, the storage device stores the data in the storage unit. A quiesce point counter whose value is updated when a quiesce point at a predetermined timing is detected while the data to be backed up is quiesced, and a last update period of the storage unit to be backed up. When data is written to any of the blocks in the data area of, the quiescent point for acquiring the last update period , which is the last update period corresponding to the block, is updated to the value of the quiesce point counter. Information acquisition department and
Based on the acquired last update period and the reference point counter indicating the backup reference point for each of the blocks held by the own device, the previous block among the blocks held by the storage unit to be backed up was previously selected. Update block detection that detects the update block, which is the block whose data has been updated since the time of the backup, and holds the acquired quiescent point counter as the reference point counter for the current backup of the block specified as the update block. A backup device characterized by having a unit. A storage device including one or more storage units that manage a storage area in a predetermined block unit detects a stationary point at a predetermined timing in a state where the data stored in the storage unit is stationary in the own device. Then, the value of the quiescent point counter held by the own device is updated, and
When the storage device writes data to any of the blocks which are a plurality of data areas of the block unit of the storage unit, the final update held by the own device in association with each of the blocks. The last update period corresponding to the block in the period is updated to the value of the quiescent point counter, and the data is updated.
The storage device outputs the quiesce point counter and the last update period in response to a request from the backup device that backs up the data stored in the storage unit.
When the backup device performs the backup, the quiesce point counter and the last update period of the storage unit to be backed up are acquired.
The backup device has a storage unit to be backed up based on the acquired last update period and a reference point counter indicating a backup reference point for each of the blocks held by the own device. The update block, which is the block whose data has been updated since the last backup, is detected from the blocks, and the acquired quiescent point counter is used as the reference point counter for the current backup of the block specified as the update block. A method of backing up a storage device, characterized in that it is retained. On the computer
When backing up the data stored in the storage unit of the storage device including one or more storage units that manage the storage area in a predetermined block unit, the storage device stores the data in the storage unit. A quiesce point counter whose value is updated when a quiesce point at a predetermined timing is detected while the data to be backed up is quiesced, and a last update period of the storage unit to be backed up. When data is written to any of the blocks in the data area of, the quiesce point for acquiring the last update period , which is the last update period corresponding to the block, is updated to the value of the quiesce point counter. The storage unit to be backed up has the information acquisition process, the acquired last update period, and a reference point counter indicating a backup reference point for each of the blocks held by the own device. The update block, which is the block whose data has been updated since the last backup, is detected from the blocks, and the acquired quiescent point counter is used as the reference point counter for the current backup of the block specified as the update block. A backup program for the storage device to execute the update block detection process to be retained.

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