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Re: XFS hangs and freezes with LSI 9265-8i controller on high i/o

To: xfs@xxxxxxxxxxx
Subject: Re: XFS hangs and freezes with LSI 9265-8i controller on high i/o
From: Michael Monnerie <michael.monnerie@xxxxxxxxxxxxxxxxxxx>
Date: Wed, 13 Jun 2012 14:13:23 +0200
In-reply-to: <20120613115934.GX32601@xxxxxxxxxxxxxxx>
Organization: it-management http://it-management.at
References: <4FD66513.2000108@xxxxxxxxx> <4FD8552C.4090208@xxxxxxxxx> <20120613115934.GX32601@xxxxxxxxxxxxxxx>
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Am Mittwoch, 13. Juni 2012, 13:59:34 schrieb Andre Noll:
> Here's what gives best performance. Of course these are also the most
> risky settings, so use with care:
>
>         Current Cache Policy: WriteBack, ReadAdaptive, Cached, Write
> Cache OK if Bad BBU, Disk Cache Policy: Enabled

I wanted to comment on the original posting, but it fits here too. Aside
from this performance perspective, in order to have a system that
survives crashes and powerouts, better use:
Disk (Write) Cache: disabled (is that Disk Cache Policy for writes, or
read+writes?)
Write Cache DISABLED if Bad BBU
While turning off disk write caches costs some performance always,
disabling the controller write cache if the bbu is dead makes the server
only slower during bbu outages, but at least it will survive a crash
then.
It depends on your needs, but I don't know an admin with a +40TB storage
that says "doesn't matter if it breaks, I'll restore from backup", as
even with disk2disk backup that takes some time.

--
mit freundlichen Grüssen,
Michael Monnerie, Ing. BSc

it-management Internet Services: Protéger
http://proteger.at [gesprochen: Prot-e-schee]
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