Received: from localhost (unknown [200.46.204.191]) by postgresql.org (Postfix) with ESMTP id AB2742E162B for ; Wed, 26 Dec 2007 14:14:12 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.191]) (amavisd-maia, port 10024) with ESMTP id 07355-03 for ; Wed, 26 Dec 2007 14:14:08 -0400 (AST) Received: from westnet.com (westnet.com [216.187.52.2]) by postgresql.org (Postfix) with ESMTP id CCB972E032A for ; Wed, 26 Dec 2007 14:14:07 -0400 (AST) Received: from westnet.com (localhost [127.0.0.1]) by westnet.com (8.14.0/8.14.0) with ESMTP id lBQIDvEG015216; Wed, 26 Dec 2007 13:13:57 -0500 (EST) Received: from localhost (gsmith@localhost) by westnet.com (8.14.0/8.13.2/Submit) with ESMTP id lBQIDu3i015211; Wed, 26 Dec 2007 13:13:57 -0500 (EST) X-Authentication-Warning: westnet.com: gsmith owned process doing -bs Date: Wed, 26 Dec 2007 13:13:56 -0500 (EST) From: Greg Smith X-X-Sender: gsmith@westnet.com To: Mark Mielke cc: Fernando Hevia , "'pgsql-performance'" Subject: Re: With 4 disks should I go for RAID 5 or RAID 10 In-Reply-To: <47728000.4000709@mark.mielke.cc> Message-ID: References: <0ea101c847d2$16f94bc0$8f01010a@iptel.com.ar> <47728000.4000709@mark.mielke.cc> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200712/364 X-Sequence-Number: 28180 On Wed, 26 Dec 2007, Mark Mielke wrote: > I believe hardware RAID 5 is also horrible, but since the hardware hides > it from the application, a hardware RAID 5 user might not care. Typically anything doing hardware RAID 5 also has a reasonable sized write cache on the controller, which softens the problem a bit. As soon as you exceed what it can buffer you're back to suffering again. -- * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD