cancel
Showing results for 
Search instead for 
Did you mean: 

Heavy disk usage on Media server when idle

BirtyB
Level 4

Hi all,

Our NBU 7.6.3 deployment is still in pre-production and yesterday, for the first time we ran a couple of test VM backups.  The backup completed successfully however almost immediately after the backup completed, and still 24 hours later, I see heavy disk reads on the LUN that hosts the Dedupe store.  If I look at the Disk tab within Windows Resource Monitor I see the following (see attachement).

This storage is connected via iSCSI if that makes a difference...

Is this expected?

Thanks in advance,

Graham

1 ACCEPTED SOLUTION

Accepted Solutions

BirtyB
Level 4

Hi all, sorry for the lack of updates.  As above the problem went away when we recreated the MSDP volume on a thick provisioned LUN.  Thanks for your help.

View solution in original post

8 REPLIES 8

BirtyB
Level 4

Another attachment showing NIC bandwidth history on the storage unit.

AAlmroth
Level 6
Partner Accredited

I'd say it is the normal maintenance jobs in your MSDP disk pool.

Have a look in the file Q:\dedupe\log\spoold\storaged.log

It should give an idea of what it is currently doing.

The spoold process should also be quite busy.

 

/A

 

 

BirtyB
Level 4

Thanks for your help.  The log is ful of these:

October 30 01:11:10 ERR [000000000A01AF40]: 25048: _storeGetCRCCheckCandidateFromJournal: can't fsync file Q:\Dedupe\databases\datacheck\crc_check_write: (invalid file descriptor)

AAlmroth
Level 6
Partner Accredited

I have never really seen that error, but the fsync would indicate it is unable to flush data to disk. Perhaps you should open a support case with Symantec.

In the meantime: Do you use antivirus scanner? Perhaps try disabling scan of Q drive, or relevant processes such as spoold.exe

 

/A

 

Nicolai
Moderator
Moderator
Partner    VIP   

Likely - MSDP pool does a lot of housekeeping (space reclaim, integrity checking etc) when idle.

http://www.symantec.com/docs/HOWTO89134

http://www.symantec.com/docs/TECH124914

jim_dalton
Level 6

I know nothing of this facet but if I were to see messages along the lines of "datacheck" and "crc " I'd be thinking: data corruption. Worrying...

JIm

BirtyB
Level 4

I've opned a case with Support.  It seems to partly be down to the fact that the MSDP LUN was thin provisioned.  I've since recreated the LUN as think provisioned and am using nbperfchk to make sure the storage is up to the task.   I'll update this thread when I know more.

BirtyB
Level 4

Hi all, sorry for the lack of updates.  As above the problem went away when we recreated the MSDP volume on a thick provisioned LUN.  Thanks for your help.