Hi
I don't know whether toasters need a day off, though I always appreciate one.
My experience has been that there are several bugs in pre-7.2.4 releases which can cause lots of WAFL scans and generally poor performance; so my advice here would be to upgrade (preferably both) the boxes to 7.2.5.1 and then recheck performance.
cheers
Kenneth
> Date: Fri, 26 Sep 2008 12:41:54 -0400
> From: tmerrill@mathworks.com
> To: toasters@mathworks.com
> Subject: do toaster need a day off? (WAFL scans)
>
>
>
> Two scenarios:
>
> 1. R200, 7.2.2, two 12 TB aggregates, 85 volumes of various sizes, 70-80% full
> snapvault secondary, ALWAYS receiving snapvaults and nearly
> ALWAYS spinning to tape.
>
> 2. 6070, 7.2.4, two 8 TB aggregates, 27 volumes between 150 and 700 GB, 60-70% full
> recent migration (via volume snapmirrors) from 980's, serves
> home directories to NFS and CIFS clients.
>
>
> We stopped all snapmirrors/snapvaults to the R200, terminated CIFS, and shut off
> NFS. CPU utilization remained 90%+ and disk reads remained high for the next
> 6-7-8 hours until it finally quieted down.
>
> After volume snapmirroring the home dirs from the 980's to the 6070, we
> re-pointed the snapvaults (modify; start -r) and allowed NFS and CIFS access.
> 5 days later, file server performance still blows (worse than the 980's --
> D'oh! Egg, meet Face; Face, meet Egg), with moderate CPU load 30-40-50%
> but high disk reads.
>
> In both cases, we determined that lots of WAFL scans were going on:
>
> container block reclamation
> volume deswizzling
> active bitmap rearrangement (of course...this NEVER seems to stop)
>
> and a few other types that have already scrolled out of my buffer.
>
> So, we figure--eventually--the WAFL scans will catch up and performance
> will go back to normal on the 6070. The performance of the R200 always
> blows.
>
>
> So...here finally is the question: do toasters need a day off?
>
> Said another way, to maintain acceptable performance and low/fast response
> times, do toasters need a goodly amount of (relatively) idle time in
> order for these WAFL scans to complete?
>
> Could the sub-optimal performance of another group of six 6070's
> that we have, that we *pound on* 7x24, be explained in part by
> always having at least the container block reclamation scan going on?
>
> Until next time...
>
> The MathWorks, Inc. 508-647-7000 x7792
> 3 Apple Hill Drive, Natick, MA 01760-2098 508-647-7001 FAX
> tmerrill@mathworks.com http://www.mathworks.com
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