From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brendan Conoboy Subject: Re: limits on raid Date: Mon, 18 Jun 2007 11:20:02 -0600 Message-ID: <4676BEC2.7090809@redhat.com> References: <18034.479.256870.600360@notabene.brown> <18034.3676.477575.490448@notabene.brown> <20070616020320.GB2002@animx.eu.org> <18035.23867.576212.859440@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: david@lang.hm Cc: Neil Brown , Wakko Warner , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org List-Id: linux-raid.ids david@lang.hm wrote: > in my case it takes 2+ days to resync the array before I can do any > performance testing with it. for some reason it's only doing the rebuild > at ~5M/sec (even though I've increased the min and max rebuild speeds > and a dd to the array seems to be ~44M/sec, even during the rebuild) With performance like that, it sounds like you're saturating a bus somewhere along the line. If you're using scsi, for instance, it's very easy for a long chain of drives to overwhelm a channel. You might also want to consider some other RAID layouts like 1+0 or 5+0 depending upon your space vs. reliability needs. -- Brendan Conoboy / Red Hat, Inc. / blc@redhat.com