Failover systems and methods for performing backup operations

• US 8,504,526 B2
• Filed: 12/30/2010
• Issued: 08/06/2013
• Est. Priority Date: 06/04/2010
• Status: Active Grant

• Current Assignee: CommVault Systems Incorporated
• Original Assignee: CommVault Systems Incorporated
• Inventors: Gokhale, Parag, Varadharajan, Prakash, Mazur, Pavlo
• Primary Examiner(s): CHANNAVAJJALA, SRIRAMA T
• Application Number:
  US12/982,165
• Publication Number:
  US 20110302140A1
• Time in Patent Office: 950 Days
• Field of Search: 707636-641, 707644-654, 707/665, 707671-675, 707/682, 714/6.21, 714/6.22, 714/6.23, 714/6.24, 714/6.3, 714 13- 16, 714/20, 718/1, 718101-105, 711/103, 711/112, 711161-162
• US Class Current: 707/648
• CPC Class Codes: G06F 11/1446 Point-in-time backing up or restoration of persistent data
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1464 for networked environments
• CPC Class Codes: G06F 11/1466 to make the backup process non-disruptive
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 11/2023 Failover techniques
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: G06F 16/113 Details of archiving lifecycle management in storage systems G06F3/0649; backup systems G06F11/1446
• CPC Class Codes: G06F 16/21 Design, administration or maintenance of databases
• CPC Class Codes: H04L 41/08 Configuration management of networks or network elements address allocation H04L61/50

Abstract

In certain embodiments, a tiered storage system is disclosed that provides for failover protection during data backup operations. The system can provide for an index, or catalog, for identifying and enabling restoration of backup data located on a storage device. The system further maintains a set of transaction logs generated by media agent modules that identify metadata with respect to individual data chunks of a backup file on the storage device. A copy of the catalog and transaction logs can be stored at a location accessible by each of the media agent modules. In this manner, in case of a failure of one media agent module during backup, the transaction logs and existing catalog can be used by a second media agent module to resume the backup operation without requiring a restart of the backup process.

Claims

1. A method for performing a backup operation in a storage system, the method comprising:

receiving with a first media agent module executing on a first computing device a plurality of data chunks to back up on a first storage device as a single backup file and as part of a current backup operation;

with the first media agent module, storing a first data chunk of the plurality of data chunks in a backup format on the first storage device;

with the first media agent module, generating a first transaction log comprising metadata of the first data chunk;

transmitting the first transaction log to a second computing device which is in networked communication with the first computing device and which is in networked communication with a third computing device that has a second media agent module executing thereon;

with the first media agent module, storing a second data chunk of the plurality of data chunks in the backup format on the first storage device;

with the first media agent module, generating a second transaction log comprising metadata of the second data chunk;

transmitting the second transaction log to the second computing device, wherein said transmitting the first and second transaction logs is performed prior to the entire backup file being stored on the first storage device;

detecting an unbalanced workload of the first media agent module prior to the entire backup file being stored on the first storage device;

subsequent to said detecting, receiving with the first media agent module an instruction to cease backing up the plurality of data chunks to the first storage device;

obtaining an index associated with a previous backup operation;

accessing from a second storage device associated with the second computing device at least some of the metadata of the first and second transaction logs;

with the second media agent module, using the accessed metadata to apply at least the first and second transaction logs to the index associated with the previous backup operation, wherein upon application of at least the first and second transaction logs to the index, the index reflects the point in the current backup operation at which the first media agent ceased backing up the plurality of data chunks to the first storage device; and

with the second media agent module, resuming performance of the current backup operation at least partly by storing, in the backup format and on the first storage device, remaining ones of the data chunks of the plurality of data chunks.

2. The method of claim 1, wherein said transmitting the first transaction log is performed prior to completing said storing of the second data chunk.

3. The method of claim 1, wherein said resuming performance comprises storing remaining ones of the plurality of data chunks on the first storage device without re-storing the first and second data chunks.

4. The method of claim 1, additionally comprising storing a complete index associated with contents of the previous backup operation, wherein the previous backup operation comprises last full backup performed on the first storage device.

5. A storage system for performing backup operations in a network environment, the storage system comprising:

a storage device configured to store backup data;

a first media agent module executing on a first computing device and communicatively coupled to the storage device, the first media agent module being configured to direct first backup operations on the storage device;

an index maintained on a second computing device, the index indicative of at least locations of contents of the backup data stored on the storage device,

wherein the first media agent module is configured to;

add data chunks to the backup data, the data chunks being part of a backup file,

for data each chunk added to the backup data on the storage device, generate a transaction log associated with the data chunk and comprising data for restoring one or more objects from the data chunk, and

transmit the transaction logs to the second computing device prior to the entire backup file being stored on the storage device; and

a second media agent module executing on a third computing device and communicatively coupled to the storage device; and

a storage manager module configured to;

schedule backup operations performed by the first and second media agent modules;

monitor a workload of the first media agent module during said storing of the backup file to the storage device; and

in response to detecting that the first media agent module has an unbalanced workload, instruct the second media agent module to assume control of backing up the backup file,

wherein the second media agent module is configured to;

access the index;

access the transaction logs;

replay the transaction logs to the index such that the index reflects the point in the backing up of the backup file at which the first media agent module failed; and

assume control of backing up the backup file to the storage device, wherein the second media agent module completes backing up the backup file without re-storing to the storage device the data chunks already stored to the storage device by the first media agent module.