3 Replies Latest reply: Jul 17, 2013 7:34 PM by Rodrigo Nascimento RSS

Spike in Write Latency Normal When Block Recommended for ReAssignment?

MRJORDANG Cyclist
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Hello NetApp Communities!

 

We have been experiencing spikes in latency (1000ms+) at or around the same time we see the errors in the messages file regarding stripe writes and block reassignment:

 

Wed Jul 17 16:10:37 CDT [filerA:raid.tetris.media.recommend.reassign.err:info]: Block recommended for reassignment on Disk /aggr0/plex0/rg0/4a.02.17 Shelf 2 Bay 17 [NETAPP   X412_HVIPC560A15 NA02] S/N [XXXXXXXXXXXxx], block #3088720 during stripe write

Wed Jul 17 16:10:37 CDT [filerA:raid.rg.readerr.repair.data:debug]: Fixing bad data on Disk /aggr0/plex0/rg0/4a.02.17 Shelf 2 Bay 17 [NETAPP   X412_HVIPC560A15 NA02] S/N [XXXXXX], block #3088720

 

Is it normal and expected behavior to exprience a noticable spike in latency when the filer recommends reassignments of blocks during stripe writes? We saw the spike in latency across all protocols.

 

It makes sense to me that there could potentially be some increase in latency, espeically if this is a sign that the disk is failing, however the spike in latency we observed today (1,000ms+) is something we would like to avoid in the future.  Normal latency hovers around 1ms.   We are running ONTAP 8.1.2P4 7-mode on a V3240.

 

 

Thanks!

-MRJG

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