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Backup Exec 2012 DLM

Created: 23 Dec 2013 | 3 comments
LSW's picture

Hi,

I hope someone could help me out with a DLM query.  Our environment consists 2 sites.  We have 1 CASO server which is used for job admin only.  It performs no backup or dedupe jobs.  We create the jobs here and point the jobs at a managed server.  Each site has 1 managed server.  We are running Backup Exec 2012 SP3 on Windows 2008 R2.  The catalog mode is in distributed mode.

I understand DLM will not delete a backup cycle even if the backup set has expired if it is the last recovery point.  What I don't understand is how DLM treats multiple copies of backup sets.

So we backup to disk with a retention period of 5 days.  We run a Full on a Friday and Inc's each day until the Full runs again on the Friday.  So DLM will not groom anything on disk despite being expired until 2 cycles are completed.  Fine.

However, after each backup we duplicate the backup to a local dedupe disk and retain for 2 weeks. We then run an optimized dedupe job to the remote site and retain for 4 weeks.  So there are now 3 copies of the backup set.

So should DLM groom the backup sets in the backup to disk location after 5 days even if it is the last recovery point as the backup sets have been duplicated to a dedupe store with a longer retention period.  Or, will it wait until cycle 2 completes then groom the backups on disk without considering the dedupe storage?  DLM for the dedupe storage is then handled separately?

Or, as each backup set is kept for 4 weeks in the off site dedupe does DLM wait for this 4 week retention to expire before grooming all backup sets together? (On disk, local dedupe and remote dedupe)

I understand tape backup sets are not considered for DLM grooming, but there is an added complication that backups are also duplicated to tape for off site recovery.

Basically, DLM isn't grooming backup sets in the backup to disk storage and I'm trying to understand why.  In most cases I can right Click and delete so there are not dependencies so I'm trying to fully understand the DLM process with multiple backup sets.

Thanks!

Lee

Operating Systems:

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LSW's picture

I've now adjusted the reg key as per the follwoing article to disable the keeping of the last backup cycle.  DLM still isn't grooming any backup sets.  I can manually delete them so there are no dependancies.  Looking in the BE Audit Log there is no DLM activity since mid November.

We've had a huge amount of problems with BE 2012.  Since SP 3 our backups have been much more stable.  This DLM issue may be a hangover from all the problems we had throughout 2013. 

To resolve this issue, the following registry value can be configured to disable the DLM rule mentioned above.

Note: Service Pack 1a (TECH186717) must be installed to proceed with the fix listed below. After installing SP1a, create the following registry key to turn on/off the "Keep the last and latest recovery chain" DLM rule.

Warning: Incorrect use of the Windows registry editor may prevent the operating system from functioning properly. Great care should be taken when making changes to a Windows registry. Registry modifications should only be carried-out by persons experienced in the use of the registry editor application. It is recommended that a complete backup of the registry and workstation be made prior to making any registry changes.

1. Open Registry on the Backup Exec Media Server
2. Start->Run->Regedit
3. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\Backup Exec For Windows\Backup Exec\Server
4. Create a new DWORD value named DeleteLastRecoverySetsOnceExpired
5. Modify the value to 1

LSW's picture

Even with DLM disabled/switched off expired backup sets on disk still aren't groomed as they should be ie once they've expired.  I'm finally seeing some activity of DLM deleting expired media sets but no way near enough.  I'm now working through 4 8TB backup to disk drives manually deleting a whole heap of expired backups.

I've not even looked at our 30Tb Dedupe drives yet.

LSW's picture

I was advised by an engineer to install Service Pack 4 - mistake!

SP4 seems to have broken everything SP3 fixed.  I was just buliding up some confidence with BE 2012 but now it feels like we've gone back 12 months.  What an absolute mess our backups are in again.

Restarting services on a daily basis, backups not running, dupe jobs to tape just stop running.  I need to reboot the library to get the tapes out when BE decides to stop writing to tape. 

Yet another call logged.