X-Original-To: pgsql-performance-postgresql.org@postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id DA1CA9F95E3 for ; Tue, 18 Jul 2006 16:43:38 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 92624-06 for ; Tue, 18 Jul 2006 16:43:30 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from smtpauth04.mail.atl.earthlink.net (smtpauth04.mail.atl.earthlink.net [209.86.89.64]) by postgresql.org (Postfix) with ESMTP id 0A37B9F94F3 for ; Tue, 18 Jul 2006 16:43:30 -0300 (ADT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=YAL7F9o9TWNd+zMdBftB8x+Yh6G/aow/hildbnfxeBEYwmKCZuV5+xftABnQuBAh; h=Message-ID:Date:From:Reply-To:To:Subject:Cc:Mime-Version:Content-Type:Content-Transfer-Encoding:X-Mailer:X-ELNK-Trace:X-Originating-IP; Received: from [209.86.224.35] (helo=elwamui-huard.atl.sa.earthlink.net) by smtpauth04.mail.atl.earthlink.net with asmtp (Exim 4.34) id 1G2vTd-0005jy-NR; Tue, 18 Jul 2006 15:43:29 -0400 Received: from 71.243.31.238 by webmail.pas.earthlink.net with HTTP; Tue, 18 Jul 2006 15:43:29 -0400 Message-ID: <3595533.1153251809718.JavaMail.root@elwamui-huard.atl.sa.earthlink.net> Date: Tue, 18 Jul 2006 15:43:29 -0400 (GMT-04:00) From: Ron Peacetree Reply-To: Ron Peacetree To: Scott Marlowe Subject: Re: RAID stripe size question Cc: PG Performance Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: EarthLink Zoo Mail 1.0 X-ELNK-Trace: acd68a6551193be5d780f4a490ca69563f9fea00a6dd62bcda3217fa91bdf0f81547bf2425c3b174350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 209.86.224.35 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200607/185 X-Sequence-Number: 20045 Have you done any experiments implementing RAID 50 this way (HBA does RAID 5, OS does RAID 0)? If so, what were the results? Ron -----Original Message----- >From: Scott Marlowe >Sent: Jul 18, 2006 3:37 PM >To: Alex Turner >Cc: Luke Lonergan , Mikael Carneholm , Ron Peacetree , pgsql-performance@postgresql.org >Subject: Re: [PERFORM] RAID stripe size question > >On Tue, 2006-07-18 at 14:27, Alex Turner wrote: >> This is a great testament to the fact that very often software RAID >> will seriously outperform hardware RAID because the OS guys who >> implemented it took the time to do it right, as compared with some >> controller manufacturers who seem to think it's okay to provided >> sub-standard performance. >> >> Based on the bonnie++ numbers comming back from your array, I would >> also encourage you to evaluate software RAID, as you might see >> significantly better performance as a result. RAID 10 is also a good >> candidate as it's not so heavy on the cache and CPU as RAID 5. > >Also, consider testing a mix, where your hardware RAID controller does >the mirroring and the OS stripes ((R)AID 0) over the top of it. I've >gotten good performance from mediocre hardware cards doing this. It has >the advantage of still being able to use the battery backed cache and >its instant fsync while not relying on some cards that have issues >layering RAID layers one atop the other.