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Date: Mon, 19 Jun 2006 08:58:47 -0400
From: "John Vincent" <lusis.org@gmail.com>
To: "Tim Allen" <tim@proximity.com.au>,
	"Scott Marlowe" <smarlowe@g2switchworks.com>,
	pgsql-performance@postgresql.org
Subject: Re: SAN performance mystery
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> I'd have to agree with you about the specific SAN/setup you're working
> with there.  I certainly disagree that it's a general property of SAN's
> though.  We've got a DS4300 with FC controllers and drives, hosts are
> generally dual-controller load-balanced and it works quite decently.


How are you guys doing the load balancing? IIRC, the RDAC driver only does
failover. Or are you using the OS level multipathing instead? While we were
on the 4300 for our AIX boxes, we just created two big RAID5 LUNs and
assigned one to each controller. With 2 HBAs and LVM stripping that was
about the best we could get in terms of load balancing.

Indeed, the EMC SANs are generally the high-priced ones too, so not
> really sure what to tell you about the poor performance you're seeing
> out of it.  Your IT folks and/or your EMC rep. should be able to resolve
> that, really...


The only exception I've heard to this is the Clarion AX150. We looked at one
and we were warned off of it by some EMC gearheads.

        Enjoy,
>
>                 Stephen
>
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<br><br><div><span class="gmail_quote"><br></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><br>I'd have to agree with you about the specific SAN/setup you're working
<br>with there.&nbsp;&nbsp;I certainly disagree that it's a general property of SAN's<br>though.&nbsp;&nbsp;We've got a DS4300 with FC controllers and drives, hosts are<br>generally dual-controller load-balanced and it works quite decently.</blockquote>
<div><br>How are you guys doing the load balancing? IIRC, the RDAC driver only does failover. Or are you using the OS level multipathing instead? While we were on the 4300 for our AIX boxes, we just created two big RAID5 LUNs and assigned one to each controller. With 2 HBAs and LVM stripping that was about the best we could get in terms of load balancing.
<br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Indeed, the EMC SANs are generally the high-priced ones too, so not<br>really sure what to tell you about the poor performance you're seeing
<br>out of it.&nbsp;&nbsp;Your IT folks and/or your EMC rep. should be able to resolve<br>that, really...</blockquote><div><br>The only exception I've heard to this is the Clarion AX150. We looked at one and we were warned off of it by some EMC gearheads.
<br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Enjoy,<br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Stephen<br><br><br>-----BEGIN PGP SIGNATURE-----
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