Received: from localhost (unknown [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id 7B0BE9FA025 for ; Tue, 11 Sep 2007 20:07:53 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.187]) (amavisd-maia, port 10024) with ESMTP id 24436-09 for ; Tue, 11 Sep 2007 20:07:42 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from noel.decibel.org (noel.decibel.org [67.100.216.10]) by postgresql.org (Postfix) with ESMTP id AD41C9FA2A7 for ; Tue, 11 Sep 2007 20:07:46 -0300 (ADT) Received: by noel.decibel.org (Postfix, from userid 1001) id 528B956500; Tue, 11 Sep 2007 23:07:45 +0000 (UTC) Received: (hashcash-sendmail, from uid 1001); Tue, 11 Sep 2007 18:07:44 -0500 Date: Tue, 11 Sep 2007 18:07:44 -0500 From: Decibel! To: pgsql-performance@postgresql.org Subject: Re: SAN vs Internal Disks Message-ID: <20070911230744.GJ38801@decibel.org> References: <20070907100446.GE1795@mathom.us> <20070907103341.GC20896@oppetid.no> <20070911205550.GA38801@decibel.org> <20070911210857.GQ1795@mathom.us> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="L3YXIp3x9iPXK/hW" Content-Disposition: inline In-Reply-To: <20070911210857.GQ1795@mathom.us> X-Operating-System: FreeBSD 6.1-RELEASE-p10 amd64 X-Distributed: Join the Effort! http://www.distributed.net User-Agent: Mutt/1.5.13 (2006-08-11) X-Hashcash: 1:20:070911:pgsql-performance@postgresql.org::MjStP00CHj2Nrwby:00000 00000000000000000000000011Lv X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200709/209 X-Sequence-Number: 26754 --L3YXIp3x9iPXK/hW Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Sep 11, 2007 at 05:09:00PM -0400, Michael Stone wrote: > On Tue, Sep 11, 2007 at 03:55:51PM -0500, Decibel! wrote: > >Also, to reply to someone else's email... there is one big reason to use > >a SAN over direct storage: you can do HA that results in 0 data loss. > >Good SANs are engineered to be highly redundant, with multiple > >controllers, PSUs, etc, so that the odds of losing the SAN itself are > >very, very low. The same isn't true with DAS. >=20 > You can get DAS arrays with multiple controllers, PSUs, etc. DAS !=3D=20 > single disk. It's still in the same chassis, though, which means if you lose memory or mobo you're still screwed. In a SAN setup for redundancy, there's very little in the way of a single point of failure; generally only the backplane, and because there's very little that's on there it's extremely rare for one to fail. --=20 Decibel!, aka Jim Nasby decibel@decibel.org EnterpriseDB http://enterprisedb.com 512.569.9461 (cell) --L3YXIp3x9iPXK/hW Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.3 (FreeBSD) iD8DBQFG5x/AdO30qud8SkgRAtINAJ4mrVwe+jPOQUAAHNO9xhhVV/P/3ACeJ7VX ebgTOjKeHteXR2ERXbqCLiA= =OEY+ -----END PGP SIGNATURE----- --L3YXIp3x9iPXK/hW--