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Date: Fri, 16 Aug 2013 22:04:02 +0200
From: Willem Jan Withagen <wjw@digiware.nl>
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To: Karl Denninger <karl@denninger.net>
Subject: Re: Fwd: Disk scheduling activity...
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On 14-8-2013 17:36, Karl Denninger wrote:
>> That would then be the Areca controller, bacause I have the feeling
>> that it always writes later.
>>
>> --WjW
>> _
> I very much doubt the ARECA is ignoring the cache-flush request.
> 
> I have several of these and can get them into a pathological state with
> TERRIBLE performance when ZFS starts doing things that demand cache
> flushes - the ARECA will perform the demanded flush which, if you have a
> lot of RAM on the board, gets real interesting in terms of performance
> impact.

I think my wording was what wrong.
What I meant is that the Areca controller was "late" in writing because
of the battery backupped cache. If it were to ignore cache-flushes that
would make it not really a very good controller.

Your remarks of getting the controller list in its workload are sort of
worrisome....

--WjW