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From: "Craig A. Berry" <craigberry@nospam.mac.com>
Newsgroups: comp.os.vms
Subject: Re: RX2800 sporadic disk I/O slowdowns
Date: Mon, 21 Oct 2024 17:43:00 -0500
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On 10/21/24 10:45 AM, Richard Jordan wrote:
> On 10/18/24 5:09 PM, Craig A. Berry wrote:
>>
>> On 10/18/24 1:26 PM, Richard Jordan wrote:
>>> Monitor during a long run shows average and peak I/O rates to the 
>>> disks with busy files at about 1/2 of what they do for normal runs. 
>>
>> That is exactly what happens when the cache battery on a RAID controller
>> dies.  Maybe yours is half-dead and sometimes takes a charge and
>> sometimes doesn't?  MSA$UTIL should show the status of your P410.
> 
> Initial check shows all good on the controller.  No disk, battery, 
> cache, etc issues.  I may add snapshotting the controller status via 
> MSA$UTIL to one of the other polling jobs in case battery or cache 
> status is varying.

Yeah, it would be good to gather whatever info you can *while* the poor
performance is happening.  It could be a lot of things, but with a
device that's designed to recover from or compensate for errors, looking
at after it's recovered from whatever is bothering it may not help much.