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verify backup

Asaf_Eskshtein
Level 3
I need to verify the backup.
some questions:

1. What verify operation do ?
does verify operation read all the data?


2. can I configure netbackup to verify automatically after backup finish ?

3. Can I configure somehow netbackup that during backup operation, it will verify data ?
i.e. after WRITE block to the tape drive, READ back the data and compare it ??
4 REPLIES 4

Sean_-
Level 5
Partner
using /usr/openv/netbackup/bin/admincmd/bpverify

TempoVisitor
Level 4
verify can be launched in command line : bpverify

Best option to use is bpverify -hoursago XX

What it does :

- Mounts a media known with active images.
- reads the data blocks in the tar files
- checks the consistency of these blocks
- checks the consistency between image catalog

What it does not do :

- access the client to see if all requested files to be backed up are ok
- check an image that is no longer in the image catalog
- allows you to verify an unknown tape. Means : you must import it first ... and the imports checks the consistency itself.

You can specify a bpverify command in any notify script that runs on the master server, to be launched after a backup or after all the backups. Find information about session_notify session_start_notify backup_exit_notify in NBU docs.

Kerkael

Stumpr2
Level 6
I just wanted to interject a little bit about the verify operation.

NetBackup can verify the contents of a backup by reading the volume and comparing its contents to what is recorded in the NetBackup catalog. Although this operation does not compare the data on the volume with the contents of the client disk, it does read each block in the image to verify that the volume is readable. (However, data corruption within a block could be possible.)

Thats from the textbook.
What it means is that it does sort of a gnu tar -tvf of the tape and compares the file listing to what is in the NetBackup catalog db. That is in essence the "verify" according to NetBackup. The only error checking is the actual ability of the gnu tar to read the tables. It doesn't do a bit for bit data check of the data itself.

Stumpr2
Level 6
If you want to test the validity of the data the best way is to do a test restore. You should always do a test restore of any new or upgraded application on the servers.

Another test would be to duplicate the image. That is just one step above using bpverify because it will at least read the data that is in the blocks. But it still falls short of the restore test because it could just be duplicating a corrupted file in the original backup.

Again best practice is the restore.