DATA RESTORATION METHOD AND SYSTEM

• US 20150261626A1
• Filed: 03/17/2015
• Published: 09/17/2015
• Est. Priority Date: 03/17/2014
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: WEN, Jijun, NIE, Yuanyuan, XU, Wentao
• Granted Patent: US 9,778,998 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor

Abstract

Embodiments of the present invention disclose a data restoration method, including: after a transaction is submitted, saving a generated transaction log to a buffer of a current node, and backing up the transaction log to a buffer of at least one backup node except the current node; writing the transaction log saved in the buffer of the current node or the transaction log backed up in the buffer of the backup node into a transaction log file in a disk, where the transaction log file in the disk is used for restoring data of the current node; and restoring, based on the transaction log file in the disk, lost data of the current node when a data loss event occurs in the current node. By means of the present invention, a risk of system data can be reduced, and durability, safety, and reliability of the system data can be improved.

Claims

1. A data restoration method, wherein the method comprises:

after a transaction is submitted, saving a generated transaction log to a buffer of a current node, and backing up the transaction log to a buffer of at least one backup node except the current node;

writing the transaction log saved in the buffer of the current node or the transaction log backed up in the buffer of the backup node into a transaction log file in a disk, wherein the transaction log file in the disk is used for restoring data of the current node; and

restoring, based on the transaction log file in the disk, lost data of the current node when a data loss event occurs in the current node.

2. The method according to claim 1, before the after a transaction is submitted, saving a generated transaction log to a buffer of a current node, and backing up the transaction log to a buffer of at least one backup node except the current node, further comprising:

setting a safety level of the current node and a backup node quantity corresponding to the safety level; and

selecting, for the current node from a node except the current node, a node of the backup node quantity corresponding to the safety level as a backup node, and using a buffer of the selected backup node as a buffer for backing up the transaction log.

3. The method according to claim 2, wherein the selecting, for the current node from a node except the current node, a node of the backup node quantity corresponding to the safety level as a backup node comprises:

selecting the backup node from a node, except the current node, adjacent to the current node, wherein a quantity of the selected backup nodes is equal to the backup node quantity corresponding to the safety level;

or selecting the backup node from a node, except the current node, comprising a vacant buffer, wherein a quantity of the selected backup nodes is equal to the backup node quantity corresponding to the safety level.

4. The method according to any one of claim 1, wherein the writing the transaction log saved in the buffer of the current node or the transaction log backed up in the buffer of the backup node into a transaction log file in a disk comprises:

determining, by the current node, whether the transaction log file in the disk comprises the transaction log saved in the buffer of the current node;

if it is determined that the transaction log file in the disk does not comprise the transaction log saved in the buffer of the current node, writing, by the current node, the transaction log saved in the buffer of the current node into the transaction log file in the disk; and

if it is determined that the transaction log file in the disk comprises the transaction log saved in the buffer of the current node, skipping writing, by the current node, the transaction log saved in the buffer of the current node into the transaction log file in the disk.

5. The method according to claim 1, wherein the writing the transaction log saved in the buffer of the current node or the transaction log backed up in the buffer of the backup node into a transaction log file in a disk comprises:

determining, by the backup node, whether the transaction log file in the disk comprises the transaction log backed up in the buffer of the backup node;

if it is determined that the transaction log file in the disk does not comprise the transaction log backed up in the buffer of the backup node, writing, by the backup node, the transaction log backed up in the buffer of the backup node into the transaction log file in the disk; and

if it is determined that the transaction log file in the disk comprises the transaction log backed up in the buffer of the backup node, skipping writing, by the backup node, the transaction log backed up in the buffer of the backup node into the transaction log file in the disk.

6. The method according to claim 1, wherein the disk comprises a current node disk supporting only access by the current node, and a backup node disk supporting only access by the backup node;

and the writing the transaction log saved in the buffer of the current node or the transaction log backed up in the buffer of the backup node into a transaction log file in a disk comprises;

writing, by the current node, the transaction log saved in the buffer of the current node into a transaction log file in the current node disk, wherein the transaction log file in the current node disk is used for restoring the data of the current node;

and

writing, by the backup node, the transaction log backed up in the buffer of the backup node into a transaction log file in the backup node disk, wherein the transaction log file in the backup node disk is used for restoring the data of the current node.

7. The method according to claim 6, wherein the restoring, based on the transaction log file in the disk, lost data of the current node when a data loss event occurs in the current node comprises:

reading the transaction log file in the current node disk;

reading the transaction log file in the backup node disk;

selecting, from the read transaction log files, a transaction log file having most complete information; and

restoring the lost data of the current node by using the transaction log file having the most complete information.

8. A data restoration system, comprising:

a saving and backup module, configured to;

after a transaction is submitted, save a generated transaction log to a buffer of a current node, and back up the transaction log to a buffer of at least one backup node except the current node;

a writing module, configured to write the transaction log saved in the buffer of the current node or the transaction log backed up in the buffer of the backup node into a transaction log file in a disk, wherein the transaction log file in the disk is used for restoring data of the current node; and

a restoration module, configured to restore, based on the transaction log file in the disk, lost data of the current node when a data loss event occurs in the current node.

9. The system according to claim 8, further comprising:

a setting module, configured to set a safety level of the current node and a backup node quantity corresponding to the safety level; and

a selecting module, configured to select, for the current node from a node except the current node, a node of the backup node quantity corresponding to the safety level as a backup node, and use a buffer of the selected backup node as a buffer for backing up the transaction log.

10. The system according to claim 9, wherein the selecting module

is further configured to select the backup node from a node, except the current node, adjacent to the current node, wherein a quantity of the selected backup nodes is equal to the backup node quantity corresponding to the safety level;

or

is further configured to select the backup node from a node, except the current node, comprising a vacant buffer, wherein a quantity of the selected backup nodes is equal to the backup node quantity corresponding to the safety level.

11. The system according to claim 8, wherein the writing module comprises:

a first determining unit, configured to;

determine whether the transaction log file in the disk comprises the transaction log saved in the buffer of the current node;

if it is determined that the transaction log file in the disk does not comprise the transaction log saved in the buffer of the current node, generate a first writing message and send the first writing message to a first writing unit; and

if it is determined that the transaction log file in the disk comprises the transaction log saved in the buffer of the current node, generate a first writing skipping message and send the first writing skipping message to the first writing unit; and

the first writing unit, configured to;

after receiving the first writing message, write the transaction log saved in the buffer of the current node into the transaction log file in the disk; and

after receiving the first writing skipping message, skip writing the transaction log saved in the buffer of the current node into the transaction log file in the disk.

12. The system according to claim 8, wherein the writing module further comprises:

a second determining unit, configured to;

determine whether the transaction log file in the disk comprises the transaction log backed up in the buffer of the backup node;

if it is determined that the transaction log file in the disk does not comprise the transaction log backed up in the buffer of the backup node, generate a second writing message and send the second writing message to a second writing unit; and

if it is determined that the transaction log file in the disk comprises the transaction log backed up in the buffer of the backup node, generate a second writing skipping message and send the second writing skipping message to the second writing unit; and

the second writing unit, configured to;

after receiving the second writing message, write the transaction log backed up in the buffer of the backup node into the transaction log file in the disk; and

after receiving the second writing skipping message, skip writing the transaction log backed up in the buffer of the backup node into the transaction log file in the disk.

13. The system according to claim 8, wherein the disk comprises a current node disk supporting only access by the current node, and a backup node disk supporting only access by the backup node;

and the writing module comprises;

a current node writing unit, configured to write the transaction log saved in the buffer of the current node into a transaction log file in the current node disk, wherein the transaction log file in the current node disk is used for restoring the data of the current node; and

a backup node writing unit, configured to write the transaction log backed up in the buffer of the backup node into a transaction log file in the backup node disk, wherein the transaction log file in the backup node disk is used for restoring the data of the current node.

14. The system according to claim 13, wherein the restoration module comprises:

a reading unit, configured to read the transaction log file in the current node disk and further configured to read the transaction log file in the backup node disk;

a selecting unit, configured to select, from the transaction log files read by the reading module, a transaction log file having most complete information; and

a restoration unit, configured to restore the lost data of the current node by using the transaction log file having the most complete information.