Received: from localhost (maia-2.hub.org [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id 5DCD39FB25F for ; Wed, 11 Jul 2007 11:05:56 -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 52258-07 for ; Wed, 11 Jul 2007 11:05:45 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from oxford.xeocode.com (unknown [62.232.55.118]) by postgresql.org (Postfix) with ESMTP id C754A9FA0EF for ; Wed, 11 Jul 2007 11:05:52 -0300 (ADT) Received: from localhost ([127.0.0.1] helo=oxford.xeocode.com) by oxford.xeocode.com with esmtp (Exim 4.67) (envelope-from ) id 1I8cp0-00013L-39; Wed, 11 Jul 2007 15:05:38 +0100 From: Gregory Stark To: "Dave Cramer" Cc: "postgresql performance list" Subject: Re: best use of an EMC SAN In-Reply-To: (Dave Cramer's message of "Wed, 11 Jul 2007 09:03:27 -0400") Organization: EnterpriseDB References: X-Draft-From: ("nnimap+mail01.enterprisedb.com:INBOX.performance" 1466) Date: Wed, 11 Jul 2007 15:05:37 +0100 Message-ID: <877ip7avda.fsf@oxford.xeocode.com> User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200707/82 X-Sequence-Number: 25766 "Dave Cramer" writes: > Assuming we have 24 73G drives is it better to make one big metalun and carve > it up and let the SAN manage the where everything is, or is it better to > specify which spindles are where. This is quite a controversial question with proponents of both strategies. I would suggest having one RAID-1 array for the WAL and throw the rest of the drives at a single big array for the data files. That wastes space since the WAL isn't big but the benefit is big. If you have a battery backed cache you might not need even that. Just throwing them all into a big raid might work just as well. -- Gregory Stark EnterpriseDB http://www.enterprisedb.com