Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763963AbXFRSdg (ORCPT ); Mon, 18 Jun 2007 14:33:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759353AbXFRSd0 (ORCPT ); Mon, 18 Jun 2007 14:33:26 -0400 Received: from caffeine.uwaterloo.ca ([129.97.134.17]:60227 "EHLO caffeine.csclub.uwaterloo.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759273AbXFRSdZ (ORCPT ); Mon, 18 Jun 2007 14:33:25 -0400 X-Greylist: delayed 1797 seconds by postgrey-1.27 at vger.kernel.org; Mon, 18 Jun 2007 14:33:25 EDT Date: Mon, 18 Jun 2007 14:33:24 -0400 To: david@lang.hm Cc: Brendan Conoboy , Neil Brown , Wakko Warner , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org Subject: Re: limits on raid Message-ID: <20070618183324.GL10006@csclub.uwaterloo.ca> References: <18034.479.256870.600360@notabene.brown> <18034.3676.477575.490448@notabene.brown> <20070616020320.GB2002@animx.eu.org> <18035.23867.576212.859440@notabene.brown> <4676BEC2.7090809@redhat.com> <20070618180327.GP10008@csclub.uwaterloo.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.13 (2006-08-11) From: lsorense@csclub.uwaterloo.ca (Lennart Sorensen) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1303 Lines: 27 On Mon, Jun 18, 2007 at 11:12:45AM -0700, david@lang.hm wrote: > simple ultra-wide SCSI to a single controller. Hmm, isn't ultra-wide limited to 40MB/s? Is it Ultra320 wide? That could do a lot more, and 220MB/s sounds plausable for 320 scsi. > I didn't realize that the rate reported by /proc/mdstat was the write > speed that was takeing place, I thought it was the total data rate (reads > + writes). the next time this message gets changed it would be a good > thing to clarify this. Well I suppose itcould make sense to show rate of rebuild which you can then compare against the total size of tha raid, or you can have rate of write, which you then compare against the size of the drive being synced. Certainly I would expect much higer speeds if it was the overall raid size, while the numbers seem pretty reasonable as a write speed. 4MB/s would take for ever if it was the overall raid resync speed. I usually see SATA raid1 resync at 50 to 60MB/s or so, which matches the read and write speeds of the drives in the raid. -- Len Sorensen - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/