MS SQL backups fail with Error 6

[Richard_Senda3]

Hello,

I recently upgraded my NetBackup system from version 7.1 to version 7.5.4.  When I did this, backups of some MS-SQL 2008 databases are failing with this error:

02/28/2013 10:28:58 - Info bphdb (pid=7548) dbclient(pid=7548) wrote first buffer(size=65536)
02/28/2013 10:29:58 - Info bphdb (pid=7548) done. status: 6
02/28/2013 10:30:00 - Error bptm (pid=11514) media manager terminated by parent process
02/28/2013 10:30:00 - Critical bptm (pid=11518) attempted to write 0 gigabytes, 188089653 bytes, it is not a multiple of 512
02/28/2013 10:30:01 - Info bphdb (pid=7548) done. status: 6: the backup failed to back up the requested files

I notice a similar error is reported in this thread https://www-secure.symantec.com/connect/forums/error-6-0

We have our backups of MS-SQL databases configured using bach files created using the NetBackup MS-SQL GUI, the batch file is configured to run backups in batches of 10.  The error always occurs on the same database at the same point in the backup - backup and truncate transaction log, so I thought there to be a problem with that particular database.  I created a backup batch file and policy just for that database - it works perfectly, so it's not the database.

I have many other clients running at version 7.5.4 so I don't belive this to be a problem with the NetBackup Master/Media servers.  We did not see this error using NetBackup 7.1 and all of the other databases on the server backup correctly, I have 2 database servers showing this error.  So I suspect the problem is with the NetBackup Client.

Any idea?

Many thanks.

[Richard_Senda3]

Believe I've found the cause of the problem.  The error occurs when taking a transaction log backup after a shrink has been made on the transaction log to remove the white space using an MS-SQL maintenance plan.  So this looks to be a bug in the NetBackup Client.

Steps to reproduce the problem:

1. Install the NetBackup 7.5.4 client onto an MS-SQL 2008 server
2. Create a 2 backup policies and batch file in NetBackup.  The first to backup the database in Full, the second to backup and truncate the transaction logs only.
3. Run the policy to take a Full backup
4. Run the policy to take a transaction log backup + truncate
5. In MS-SQL server, shrink the transaction log to remove the white space
6. In NetBackup, re-run the policy to take a backup and truncate of the transaction logs only

You'll find it will fail with error code 6.

7. Re-run the policy to backup and truncate the transaction logs.  This time it will complete successfully.

[Richard_Senda3 · Accepted solution]

Actually this is due to a bug in NetBackup 7.5.0.4, it's fixed in NetBackup 7.5.0.5