Re: Oracle 10g hangs intermittently waiting for I/O

From: Mathias Magnusson <mathias.magnusson_at_gmail.com>
Date: Mon, 18 May 2009 08:04:01 +0200
Message-ID: <8580d4110905172304j69f0b2a7iadfca0dae134ba69_at_mail.gmail.com>

Any chance you can talk the storage guys into letting you test with raid 1+0 just to see if it helps? It probably (as in if I/O is your problem, raid 5 isn't helping) will, but if you tell them that then they will feel their authority being questioned.

I'm sure Cary was looking for this as being the problem you're facing. It will be hard for your storage guys to see the problem as it is hiding in the whole raid 5 architecture. I just recently got a similar change implemented and the storage guys were more or less saying that the improvement must be due to something else.

Mathias

2009/5/17 Paweł Kotlarz <pkotla_at_go2.pl>

> Yes, all volumes are RAID-5 sets. I am now working with the storage guys
> and hope that we will be able to thoroughly check all the subsystems. I
> will share our findings to the list.
>
> Thanks for all suggestions!
>
> Pawel
>
> On 2009-05-16 22:02, Cary Millsap wrote:
>
>> I keep thinking "RAID cache flush" as I read this thread, but I don't
>> think I've seen anyone mention it yet. RAID 5 perchance? I hate guessing
>> instead of measuring...
>>
>> Cary Millsap
>> Method R Corporation
>> http://method-r.com
>> http://carymillsap.blogspot.com
>> http://twitter.com/cary_millsap
>>
>>
>> 2009/5/16 Rajeev Prabhakar <rprabha01_at_gmail.com <mailto:
>> rprabha01_at_gmail.com>>
>>
>> Hi Pawel,
>>
>> In no particular order, please check with your sysadmins/storage admins
>> about the following :
>>
>> a) Queue depth of the LUNs / associated optimal settings for your
>> storage.
>>
>> b) Any unsuccessful microcode/firmware upgrade on the FC fabric.
>>
>> c) Double check for any combination of any FC/non-FC drives
>> OR any failure of drives/associated raid group rebuild errors.
>>
>> d) LUN level i/o statistics and any out of ordinary observations.
>>
>> -Rajeev
>>
>>
>> 2009/5/16 Paweł Kotlarz <pkotla_at_go2.pl>:
>> > Thanks, Rajeev. I appreciate your help very much!
>> >
>> > Pawel
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>>
>>
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Received on Mon May 18 2009 - 01:04:01 CDT