From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261586AbTJHXoT (ORCPT ); Wed, 8 Oct 2003 19:44:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261744AbTJHXoT (ORCPT ); Wed, 8 Oct 2003 19:44:19 -0400 Received: from main.gmane.org ([80.91.224.249]:52619 "EHLO main.gmane.org") by vger.kernel.org with ESMTP id S261586AbTJHXoR (ORCPT ); Wed, 8 Oct 2003 19:44:17 -0400 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: mru@users.sourceforge.net (=?iso-8859-1?q?M=E5ns_Rullg=E5rd?=) Subject: Re: Software RAID5 with 2.6.0-test Date: Thu, 09 Oct 2003 01:44:13 +0200 Message-ID: References: <1065655452.13572.50.camel@torrey.et.myrio.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Complaints-To: usenet@sea.gmane.org User-Agent: Gnus/5.1002 (Gnus v5.10.2) XEmacs/21.4 (Rational FORTRAN, linux) Cancel-Lock: sha1:WYxVwUBnt7Iv34RZVhZgaEFRXzE= Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Torrey Hoffman writes: > My experience: > > I'm running 2.6.0-test6 on a dual pentium 3 with software raid-5 across > 5 disks on two different IDE hardware controllers (VIA and Promise). > I've got a 224 GB reiserfs partition on that. > > After 8 days uptime, it doesn't seem to have blown up yet. However I > don't stress it heavily - just a nightly rsync or two which does a lot > of reading and writing, and I export my music collection on it via NFS, > which is a low level of read activity. When I tried it, I was running 2.6.0-test4. The RAID5 was 4 120 GB Seagate disks on a Highpoint controller. On top of that, I had LVM, with ext3 fs. After just minutes, strange things started happening to files. Some had random bits changed in the inode, others were just trashed. e2fsck complained a great deal. I went back to 2.4.21, which is working OK. A couple of things bother me, though. In the dmesg output there are many of these: raid5: switching cache buffer size, 8192 --> 1024 raid5: switching cache buffer size, 1024 --> 4096 raid5: switching cache buffer size, 4096 --> 1024 raid5: switching cache buffer size, 1024 --> 4096 raid5: switching cache buffer size, 4096 --> 1024 ISTR reading somewhere, that this has a bad impact on performance. The other thing that I don't like, is the performance of the RAID array. The disks individually give ~40 MB/s read speed, but the array only measures 25 MB/s. I was of the impression, that RAID5 would give read speeds at least equal to the underlying disks. Is this incorrect? -- Måns Rullgård mru@users.sf.net