Under certain circumstances, NetBackup may skip a random stream during SharePoint backups, resulting in an inability to restore.

  • Article ID:100009644
  • Modified Date:
  • Product(s):

Problem

Under certain circumstances, if a SharePoint client has additional stream data that was not present at the time of the previous backup attempt, the backup job may skip a random stream.  Skipped stream data will not be available for restore.  There is no indication that this part of the backup is missed and the missing stream may not be backed up until the NetBackup Policy Execution Manager (nbpem) is restarted.    

This issue will occur if the following conditions are met: 

  • The SharePoint client has additional streams that were not present at the time of the previous backup of the farm.
  • The SharePoint client has a stream(s) that were removed from the client, then added back in, while successful backups have run in the interim.

When a SharePoint stream is added and there is no lastbackup value for the stream, the nbpem process will receive a value for an incorrect window.  In the case where the SharePoint policy has not run successfully during the previous backup window, and the original backup had more than one stream, a random stream will be skipped with no indication of its absence in the backup.

In the case where the original backup had only one stream and a new client is added to the farm, status code: 196 (client backup was not attempted because backup window closed) will be reported.

Error Message

In both scenarios where this issue may be experienced, the log files will show similar information.

In the case where status code 196 is reported, the nbpem logs show that the window that is being returned is from the day before.

From nbpem logs with DebugLevel=4 set, the backup job is started and calculation window is reviewed:

04/17/13 04:03:17.469 queueing PEMpreprocessed : jobid=39542, jobSubtype=514, cancelFlags=0, filelist len=2, snapid=[SHAREPOINT_CLIENT]_1366185667, clientName=[SHAREPOINT_CLIENT2],alt_clientName=[SHAREPOINT_CLIENT]
04/17/13 04:03:17.578  Using inherited time for calculation 2013/04/16 05:31:33 (1366104693)(Scheduler.cpp:1339)
04/17/13 04:03:17.578  isSchedWindowOpen returned (schedule=Full, openAt=1366099200, closeAt=1366117200, isOpen=true)

Then an "out of window" message:

04/17/13 04:03:17.578  Will not run stream 1 because it starts outside of window

Review of the ctimes used in the window calculation show that the previous day's window was used.  In this example, the ctime values thisStart=1366099200, thisClose=1366117200 correspond to April 16:

1366099200 = Tue Apr 16 04:00:00 2013
1366117200 = Tue Apr 16 09:00:00 2013

However, it can be seen above that these logs were generated when this job was run: April 17.

In the case where a stream is skipped, similar log file messages will be displayed, with the difference that one random stream may not run.

Cause

This issue is caused by a product defect. 

Solution

The formal resolution for this issue (Etrack 3204792) is included in the following release:

  • NetBackup 7.5 Maintenance Release 6 (7.5.0.6)

NetBackup 7.5.0.6 is available now.  Please refer to the Related Article linked below for more information.

Workaround:
Stopping and restarting the nbpem process after adding clients to a SharePoint farm will prevent streams from being skipped.

When status code 196 is reported, the missed stream will be rerun shortly after the error or completion of the added stream.  This is because calculation of the next due time is completed whenever a backup job exits.

Best Practices:
Veritas strongly recommends the following best practices:

1. Always perform a full DR backup prior to making any changes to your environment.
2. Always make sure that your environment is running the latest version and patch level.
3. Perform periodic "test" restores.

Applies To

This issue affects NetBackup 7.x (through 7.5.0.5).

Was this content helpful?

Get Support