On Thu, Jan 24, 2013 at 12:22 PM, Blake Hudson <bl...@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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