Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 2D9912E4347 for ; Thu, 24 Jan 2008 14:28:52 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 64435-01-8 for ; Thu, 24 Jan 2008 14:28:51 -0400 (AST) Received: from news.hub.org (news.hub.org [200.46.204.72]) by postgresql.org (Postfix) with ESMTP id F36052E4605 for ; Thu, 24 Jan 2008 13:34:19 -0400 (AST) Received: from news.hub.org (news.hub.org [200.46.204.72]) by news.hub.org (8.14.1/8.14.1) with ESMTP id m0OHYHW5005734 for ; Thu, 24 Jan 2008 13:34:18 -0400 (AST) (envelope-from news@news.hub.org) Received: (from news@localhost) by news.hub.org (8.14.1/8.14.1/Submit) id m0OH4ZxS088197 for pgsql-performance@postgresql.org; Thu, 24 Jan 2008 13:04:36 -0400 (AST) (envelope-from news) From: Chris Browne X-Newsgroups: pgsql.performance Subject: Re: Making the most of memory? Date: Thu, 24 Jan 2008 11:23:02 -0500 Organization: cbbrowne Computing Inc Lines: 30 Message-ID: <60r6g7kxax.fsf@dba2.int.libertyrms.com> References: <4796BE84.9030803@centriccrm.com> <47979C15.3040406@burntmail.com> <4797A8B3.5040605@janestcapital.com> <82tzl39u55.fsf@mid.bfk.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Complaints-To: usenet@news.hub.org User-Agent: Gnus/5.1008 (Gnus v5.10.8) XEmacs/21.4.21 (linux) Cancel-Lock: sha1:UFsZyKaF/cKVjCr3z7Wsbx473/g= To: pgsql-performance@postgresql.org X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200801/216 X-Sequence-Number: 28455 fweimer@bfk.de (Florian Weimer) writes: >> So, that web site seems to list products starting at about 32GB in a >> separate rack-mounted box with redundant everything. I'd be more >> interested in just putting the WAL on an SSD device, so 500MB or 1GB >> would be quite sufficient. Can anyone point me towards such a device? > > A dedicated RAID controller with battery-backed cache of ssuficient > size and two mirrored disks should not perform that bad, and has the > advantage of easy availability. That won't provide as "souped up" performance as "WAL on SSD," and it's from technical people wishing for things that some of those things actually emerge... It appears that the SSD market place is going pretty "nuts" right now as vendors are hawking flash-based SSD devices that are specifically targeted at replacing disk drives for laptops. I agree that there would be a considerable value for DBMS applications in having availability of a device that combines the strengths of both Flash (persistence) and DRAM (sheer volume of IOPs) to provide something better than they offered alone. I expect that the standard size for this is more likely to be 32GB than 1GB, what with modern shrinkage of physical sizing... -- let name="cbbrowne" and tld="linuxfinances.info" in String.concat "@" [name;tld];; http://www3.sympatico.ca/cbbrowne/spiritual.html "When we write programs that "learn", it turns out that we do and they don't." -- Alan J. Perlis