Load spikes when new email arrives

[francis picabia]

On Thu, Jan 24, 2013 at 12:22 PM, Blake Hudson <blake at ispn.net> wrote:

>
>
> There are a couple suggestions I'd like to put forth. First, improper
> partition alignment is generally masked by the controller cache. I
> strongly encourage you to check that your RAID array is making use of
> this cache by enabling the WriteBack caching option on this array,
> especially if your PERC card has a BBU (I think this was optional on
> perc 5). You can install the MegaCLI tool from LSI to verify this (can
> also be checked from OpenManage or reboot into the controller BIOS).
>
>
Thanks for this tip.  It put me on to what is wrong.

Jan 18 07:25:39 myserv Server Administrator: Storage Service EventID: 2335
Controller event log: BBU disabled; changing WB virtual disks to WT:
Controller 0 (PERC 5/i Integrated)

Bingo!  We had write back all along, and the performance tanked when it
fell back to write through.  I was wondering why my policy change attempts
were flipping back when I tried testing WB this morning!

This explains everything we've been seeing.  Wow.  Gotta call Dell.

Thanks everyone for the assistance.  I didn't think a battery which shows OK
status in omreport could wound us!
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