Verification of metadata integrity for inode-based backups

• US 8,600,953 B1
• Filed: 06/08/2007
• Issued: 12/03/2013
• Est. Priority Date: 06/08/2007
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Corporation (NortonLifeLock Inc.)
• Inventors: Gerber, Clyde Delton
• Primary Examiner(s): Choi, Yuk Ting
• Application Number:
  US11/760,501
• Time in Patent Office: 2,370 Days
• Field of Search: None
• US Class Current: 707/687
• CPC Class Codes: G06F 11/1458 Management of the backup or restore process

Abstract

Systems, methods, and computer-readable memory media for performing various methods for verification of inode metadata are disclosed. This may be done, in various embodiments, by splitting the metadata for a given inode into two or more components. Each component may then be transmitted as an inode message from, for example, a data server to a backup server. Counters may be used to determine if all messages have been received for a group of inodes. Temporary data structures may be created dynamically to aid in the verification of the inode metadata. In one embodiment, received inode metadata is used to indicate the presence (e.g., in a catalog) of an invalid reference from a child inode to its parent inode. A metadata catalog may be created and used during the restore process to “browse” a portion of the backed up data.

Claims

1. A non-transitory computer-readable memory medium storing program instructions that are computer executable on a backup server to:

receive a plurality of inode messages, wherein each of the received plurality of inode messages includes inode metadata for one of a plurality of inodes that is being backed up, wherein the plurality of received inode messages includes messages of a first type and messages of a second type, wherein, for a given inode being backed up, the first type of inode message includes name and parent information for the given inode, and wherein the second type of inode message includes additional metadata for the given inode; and

use the received plurality of inode messages to determine whether the inode metadata includes errors by, excluding duplicative messages, determining whether an equal number of messages of the first type and messages of the second type are received by the backup server.

2. The non-transitory computer-readable memory medium of claim 1, wherein the program instructions are computer executable on the backup server to:

increment a counter value for each received inode message of the first type;

decrement the counter value for each received inode message of the second type;

after receiving the plurality of inode messages, determine whether the current counter value has changed from an initial counter value set prior to receiving any of the plurality of inode messages.

3. The non-transitory computer-readable memory medium of claim 1, wherein the program instructions are usable to create and update a temporary data structure that includes inode metadata from the received plurality of inode messages.

4. The non-transitory computer-readable memory medium of claim 1, wherein the plurality of inode messages are received via an NDMP connection.

5. The non-transitory computer-readable memory medium of claim 1, wherein determining whether the inode metadata includes errors includes determining whether the inode metadata is incomplete or determining whether the inode metadata includes an invalid reference.

6. A non-transitory computer-readable memory medium storing program instructions that are computer executable to:

create or update a backup catalog associated with data backed up from a first server using an inode-based backup;

traverse at least a directory portion of the backup catalog to determine whether metadata associated with each of a plurality of directories listed in the backup catalog includes a valid reference to a parent directory of that directory;

in response to detecting that metadata for a first of the plurality of directories includes an invalid reference to a parent directory, determine an inode on the first server corresponding to the parent directory of the first directory; and

provide a report that includes the determined inode corresponding to the parent directory of the first directory.

7. The non-transitory computer-readable memory medium of claim 6, wherein the program instructions are computer executable to:

receive a plurality of inode messages from the first server, wherein each of the received inode messages includes inode metadata for one of a plurality of inodes that is located on the first server and is being backed up to the backup server; and

use the received plurality of inode messages to create or update the backup catalog.

8. The non-transitory computer-readable memory medium of claim 7, wherein the plurality of inode messages are received via an NDMP connection.

9. A backup server, comprising:

a processor unit including one or more processors;

a memory subsystem storing program instructions executable by the processor unit to;

receive a plurality of inode messages from a first server coupled to the backup server, wherein each of the received plurality of inode messages includes inode metadata for one of a plurality of inodes that is located on the first server and is being backed up to the backup server, wherein the plurality of received inode messages includes messages of a first type and messages of a second type, wherein, for a given inode being backed up, the first type of inode message includes name and parent information for the given inode, and wherein the second type of inode message includes additional metadata for the given inode; and

use the received plurality of inode messages to determine whether the inode metadata includes errors by determining, for each of the plurality of inodes, whether the received plurality of inode messages includes at least one message of the first type and at least one message of the second type.

10. The backup server of claim 9, wherein the plurality of inode messages are received via an NDMP connection.

11. The backup server of claim 9, wherein the memory subsystem stores program instructions that are executable by the processor unit to:

upon receiving an initial message for a given inode, store metadata included in the initial message in a first data structure;

upon determining that at least one inode message of the first type and at least one inode message of the second type have been received for the given inode, move metadata for the given inode from the first data structure into a second data structure; and

upon receiving all of the plurality of inode messages, identify inodes with information remaining in the first data structure as having incomplete metadata.

12. The backup server of claim 11, wherein the memory subsystem stores program instructions that are executable by the processor unit to:

use the second data structure to update a catalog, wherein the catalog is usable to restore the plurality of inodes.

13. The backup server of claim 9, wherein the memory subsystem stores program instructions that are executable by the processor unit to:

create or update a catalog using the received plurality of inode messages;

for a given directory listed in the catalog that is not determined to have a valid parent directory reference, determine an inode on the first server that corresponds to the actual parent of the given directory.