X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 921949DC948 for ; Sat, 24 Dec 2005 18:25:01 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 53742-01 for ; Sat, 24 Dec 2005 18:25:02 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from smtpauth07.mail.atl.earthlink.net (smtpauth07.mail.atl.earthlink.net [209.86.89.67]) by postgresql.org (Postfix) with ESMTP id 1FD149DC874 for ; Sat, 24 Dec 2005 18:24:59 -0400 (AST) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=aruuIyJ/auGr5FBxOlr1lGjvjRv/Sk8yrxbm95XeTsGQRjqoxunussFay9msn3Ts; h=Received:Message-Id:X-Mailer:Date:To:From:Subject:In-Reply-To:References:Mime-Version:Content-Type:X-ELNK-Trace:X-Originating-IP; Received: from [70.22.244.95] (helo=ron-6d52adff2a6.earthlink.net) by smtpauth07.mail.atl.earthlink.net with asmtp (Exim 4.34) id 1EqHoy-0007OU-Mc; Sat, 24 Dec 2005 17:25:00 -0500 Message-Id: <6.2.5.6.0.20051224171301.01dd4e00@earthlink.net> X-Mailer: QUALCOMM Windows Eudora Version 6.2.5.6 Date: Sat, 24 Dec 2005 17:24:58 -0500 To: "Joshua D. Drake" , pgsql-performance@postgresql.org From: Ron Subject: Re: What's the best hardver for PostgreSQL 8.1? In-Reply-To: <43ADC0A8.20503@commandprompt.com> References: <43A84D03.7090002@ritek.hu> <200512212209.50234.caseroj@comcast.net> <200512212231.55100.caseroj@comcast.net> <20051224135042.484c6e32.frank@wiles.org> <6.2.5.6.0.20051224161551.01dc5d98@earthlink.net> <43ADC0A8.20503@commandprompt.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed X-ELNK-Trace: acd68a6551193be5d780f4a490ca69563f9fea00a6dd62bcd6618f7f2ce86a2ccc454cf2980d9812350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 70.22.244.95 X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.373 required=5 tests=[AWL=-0.106, DNS_FROM_RFC_ABUSE=0.479] X-Spam-Score: 0.373 X-Spam-Level: X-Archive-Number: 200512/599 X-Sequence-Number: 16420 At 04:42 PM 12/24/2005, Joshua D. Drake wrote: >>If you've got the budget or are dealing with small enough physical >>storage needs, by all means use RAID 10. OTOH, if you are dealing >>with large enterprise class apps like Sarbanes Oxley compliance, >>medical and/or insurance, etc, etc, the storage needs can get so >>large that RAID 10 for everything or even most things is not >>possible. Even if economically feasible. >> >>RAID levels are like any other tool. Each is useful in the proper >>circumstances. >There is also RAID 50 which is quite nice. The "quite nice" part that Joshua is referring to is that RAID 50 gets most of the write performance of RAID 10 w/o using nearly as many HD's as RAID 10. OTOH, there still is a significant increase in the number of HD's used, and that means MBTF's become more frequent but you are not getting protection levels you would with RAID 10. IME RAID 50 gets mixed reviews. My two biggest issues are a= Admin of RAID 50 is more complex than the other commonly used versions (1, 10, 5, and 6) b= Once a HD failure takes place, you suffer a _permenent_ performance drop, even after the automatic volume rebuild, until you take the entire RAID 50 array off line, reinitialize it, and rebuild it from scratch. IME "a" and "b" make RAID 50 inappropriate for any but the biggest and most dedicated of DB admin groups. YMMV, Ron