Received: from localhost (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id D85C364FDED for ; Wed, 10 Dec 2008 11:50:36 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 53682-05 for ; Wed, 10 Dec 2008 11:50:33 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from oak.highrise.ca (oak.highrise.ca [70.38.99.169]) by mail.postgresql.org (Postfix) with ESMTP id 7FA7D64FD8A for ; Wed, 10 Dec 2008 11:50:33 -0400 (AST) Received: from localhost (localhost [127.0.0.1]) by oak.highrise.ca (Postfix) with ESMTP id 5EB28AC05B; Wed, 10 Dec 2008 10:52:08 -0500 (EST) Date: Wed, 10 Dec 2008 10:52:08 -0500 From: Aidan Van Dyk To: Mario Weilguni Cc: "Joshua D. Drake" , Scott Marlowe , pgsql-performance@postgresql.org Subject: Re: Experience with HP Smart Array P400 and SATA drives? Message-ID: <20081210155208.GR26596@yugib.highrise.ca> References: <4934FE60.30702@sime.com> <493E6023.3030800@sime.com> <1228838308.13962.0.camel@jd-laptop.pragmaticzealot.org> <20081209161750.GO26596@yugib.highrise.ca> <493FB619.5060205@sime.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="PBFvsYHMgDsH56j5" Content-Disposition: inline In-Reply-To: <493FB619.5060205@sime.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0 tagged_above=0 required=5 tests=none X-Spam-Level: X-Archive-Number: 200812/118 X-Sequence-Number: 32154 --PBFvsYHMgDsH56j5 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline * Mario Weilguni [081210 07:31]: > Why not? I know it's not performing as good as RAID-10, but it does not > waste 50% diskspace. RAID-6 is no option, because the performance is > even worse. And, on another system with RAID-5 + spare and SAS drives, > the same controller is working very well. Like Scott said, it's all about trade-offs. With raid5, you get abysmal write performance, "make me not sleep at night" inconsistent parity issues, and a degraded mode that will a nightmare ... ... and as a trade-off you save a little money, and get good "read only" performance ... ... as long as you don't ever have a disk or system crash ... ... or can afford to rebuild if you do ... ... etc ... -- Aidan Van Dyk Create like a god, aidan@highrise.ca command like a king, http://www.highrise.ca/ work like a slave. --PBFvsYHMgDsH56j5 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iD8DBQFJP+WouVxNPsxNPScRAhAuAKCihHJUGe04ncnfFs443sOcBQzYLACggrGc C7eVmVMmd+5Zma5XZFBrg00= =5gvG -----END PGP SIGNATURE----- --PBFvsYHMgDsH56j5--