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Re: [Xen-users] Xen and I/O Intensive Loads

To: Nick Couchman <Nick.Couchman@xxxxxxxxx>
Subject: Re: [Xen-users] Xen and I/O Intensive Loads
From: Pasi Kärkkäinen <pasik@xxxxxx>
Date: Wed, 26 Aug 2009 20:32:59 +0300
Cc: XEN Mailing List <xen-users@xxxxxxxxxxxxxxxxxxx>
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On Wed, Aug 26, 2009 at 10:01:13AM -0600, Nick Couchman wrote:
> Hi, folks, 
> The disk volume for the e-mail is on my SAN, and I've attached the FC LUN to 
> my Xen host

Does the SAN LUN perform OK from dom0 without any domUs running?

> I'm running into an issue with high I/O wait on the box (~250%) and large 
> load averages (20-40 for the 1/5/15 minute average).

Do you have iowait on dom0, or only in domU?

Try running "iostat 1" in both dom0 and domU.

Also, have you dedicated a cpu core only for dom0?

> I'm running Xen 3.2.0 on SLES 10 SP2, on a Dell PowerEdge R610 server.  The 
> FC HBA is a QLE2462, dual-channel 4Gb FC card.  Any help, hints, etc., are 
> greatly appreciated! 

You could also try updating to SLES11.

-- Pasi

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