Received: from localhost (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 3BDBA64FC4C for ; Wed, 10 Dec 2008 03:45:42 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 70554-05 for ; Wed, 10 Dec 2008 03:45:39 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from mx.inode.at (mx07.lb01.inode.at [62.99.145.7]) by mail.postgresql.org (Postfix) with ESMTP id 9330364FC57 for ; Wed, 10 Dec 2008 03:45:39 -0400 (AST) Received: from [85.124.56.44] (port=5349 helo=[10.192.17.33]) by smartmx-07.inode.at with esmtp (Exim 4.50) id 1LAJlH-0007FB-UH; Wed, 10 Dec 2008 08:45:36 +0100 Message-ID: <493F739C.9080800@sime.com> Date: Wed, 10 Dec 2008 08:45:32 +0100 From: Mario Weilguni User-Agent: Thunderbird 2.0.0.18 (X11/20081125) MIME-Version: 1.0 To: Scott Marlowe CC: Alan Hodgson , pgsql-performance@postgresql.org Subject: Re: Experience with HP Smart Array P400 and SATA drives? References: <4934FE60.30702@sime.com> <49395B57.EE98.0025.0@wicourts.gov> <200812051530.01258@hal.medialogik.com> <493E61E1.1020303@sime.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0 tagged_above=0 required=5 tests=none X-Spam-Level: X-Archive-Number: 200812/109 X-Sequence-Number: 32145 Scott Marlowe schrieb: > On Tue, Dec 9, 2008 at 5:17 AM, Mario Weilguni wrote: > >> Alan Hodgson schrieb: >> >>>>>>> Mario Weilguni wrote: >>>>>>> >>>>>>> >>>>> strange values. An individual drive is capable of delivering 91 >>>>> MB/sec >>>>> sequential read performance, and we get values ~102MB/sec out of a >>>>> 8-drive RAID5, seems to be ridiculous slow. >>>>> >>> What command are you using to test the reads? >>> >>> Some recommendations to try: >>> >>> 1) /sbin/blockdev --setra 2048 device (where device is the partition or >>> LVM volume) >>> >>> 2) Use XFS, and make sure your stripe settings match the RAID. >>> >>> Having said that, 102MB/sec sounds really low for any modern controller >>> with 8 drives, regardless of tuning or filesystem choice. >>> >>> >>> >> First, thanks alot for this and all the other answers. >> >> I measured the raw device performance: >> dd if=/dev/cciss/c0d0 bs=64k count=100000 of=/dev/null >> >> I get poor performance when all 8 drives are configured as one, large >> RAID-5, and slightly poorer performance when configured as JBOD. In >> production, we use XFS as FS, but I doubt this has anything to do with FS >> tuning. >> > > Yeah, having just trawled the pgsql-performance archives, there are > plenty of instances of people having terrible performance from HP > smart array controllers before the P800. Is it possible for you to > trade up to a better RAID controller? Whichever salesman sold you the > P400 should take one for the team and make this right for you. > > A customer of us uses the P400 on a different machine, 8 SAS drives (Raid 5 as well), and the performance is very, very good. So we thought it's a good choice. Maybe the SATA drives are the root of this problem?