From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id 021107F8C for ; Sun, 2 Feb 2014 15:31:00 -0600 (CST) Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by relay1.corp.sgi.com (Postfix) with ESMTP id C9F288F8040 for ; Sun, 2 Feb 2014 13:31:00 -0800 (PST) Received: from ipmail07.adl2.internode.on.net (ipmail07.adl2.internode.on.net [150.101.137.131]) by cuda.sgi.com with ESMTP id lmbxCRxXiUGqEJAt for ; Sun, 02 Feb 2014 13:30:59 -0800 (PST) Date: Mon, 3 Feb 2014 08:30:30 +1100 From: Dave Chinner Subject: Re: relationship of nested stripe sizes, was: Question regarding XFS on LVM over hardware RAID. Message-ID: <20140202213030.GQ2212@dastard> References: <7A732267-B34F-4286-9B49-3AF8767C0B89@colorremedies.com> <52ED4143.6090303@hardwarefreak.com> <52ED6AAF.6030703@hardwarefreak.com> <98961D3F-769D-44A9-98A8-FC7867893138@colorremedies.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <98961D3F-769D-44A9-98A8-FC7867893138@colorremedies.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Chris Murphy Cc: "stan@hardwarefreak.com Hoeppner" , xfs On Sun, Feb 02, 2014 at 11:09:11AM -0700, Chris Murphy wrote: > On Feb 1, 2014, at 2:44 PM, Stan Hoeppner > wrote: > > On 2/1/2014 2:55 PM, Chris Murphy wrote: > >> On Feb 1, 2014, at 11:47 AM, Stan Hoeppner > >> wrote: > > When nesting stripes, the chunk size of the outer stripe is > > -always- equal to the stripe width of each inner striped array, > > as I clearly demonstrated earlier: > > Except when it's hardware raid6, and software raid0, and the user > doesn't know they need to specify the chunk size in this manner. > And instead they use the mdadm default. What you're saying makes > complete sense, but I don't think this is widespread knowledge or > well documented anywhere that regular end users would know this by > and large. And that is why this is a perfect example of what I'd like to see people writing documentation for. http://oss.sgi.com/archives/xfs/2013-12/msg00588.html This is not the first time we've had this nested RAID discussion, nor will it be the last. However, being able to point ot a web page or or documentation makes it a whole lot easier..... Stan - any chance you might be able to spare an hour a week to write something about optimal RAID storage configuration for XFS? Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs