Message-ID: <47C45B80.6090907@redhat.com>
Date: Tue, 26 Feb 2008 13:33:36 -0500
From: Chris Snook <csnook@redhat.com>
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To: Andre Noll <maan@systemlinux.org>
CC: adam radford <aradford@gmail.com>, Tony Battersby <tonyb@cybernetics.com>,
       =?ISO-8859-1?Q?Johannes_W=F6rner?= 
	<johannes.woerner@tuebingen.mpg.de>,
       James Bottomley <James.Bottomley@HansenPartnership.com>,
       linux-scsi <linux-scsi@vger.kernel.org>,
       linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Performance problems with 3ware 9500S-4LP and 2.6.25-rc3
References: <20080226174314.GA30767@skl-net.de>
In-Reply-To: <20080226174314.GA30767@skl-net.de>
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Andre Noll wrote:
> we are experiencing massive performance problems with two of our
> Linux servers that contain 3ware controllers on a Tyan mainboard and
> a couple of 1T disks.
> 
> During the daily cron job that uses rsync to sync a 500G file system
> from another machine to the raid on the 3ware controller the load
> jumps up, and the machine becomes sluggish as hell. For example, an
> ssh login to that machine takes minutes to complete and ldap becomes
> unreliable while the rsync job is running. Even Nagios complains
> about the machine being down while rsync is running.

You're putting your box under astronomical load.  This is generally 
regarded as a bad idea, regardless of how well your storage controller 
is performing.  Can you measure the single-threaded throughput (say, 
coping one huge file, and then syncing) to give us a baseline 
performance figure?  rsync will happily peg your box, your network, and 
your cat if you let it.

	-- Chris
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