From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luca Berra Subject: Re: [linux-lvm] cache buffer size Message-ID: <20021108081141.GA32671@percy.comedia.it> References: <20021107175801.A8382@sistina.com> Mime-Version: 1.0 Content-Disposition: inline In-Reply-To: <20021107175801.A8382@sistina.com> Sender: linux-lvm-admin@sistina.com Errors-To: linux-lvm-admin@sistina.com Reply-To: linux-lvm@sistina.com List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: Date: Fri Nov 8 02:12:01 2002 List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" Content-Transfer-Encoding: 7bit To: linux-lvm@sistina.com On Thu, Nov 07, 2002 at 05:58:01PM +0100, Heinz J . Mauelshagen wrote: >On Wed, Nov 06, 2002 at 11:17:05AM -0600, Steve Best wrote: >Indeed snapshot exception table ios go by blocks of 1k. > >Puting the snapshot store on the same device as the original is not >recommended in general for performance reasons. > >In case 1k blocks are possible with JFS: > >if snapshots are used regularly and there's no seperate PV to put the >snapshot onto, you might want to create a 1k blocked jfs and try if >that performs better than the RAID 5 stripe cache flush penalty with the 4k >blocked filesystem. hello, is there any chance of having snapshots with 4k blocks for the exception table (configurable), i want to use snapshot for backing up my root vg but i also have swap there and it is locked to do page-sized io (4k on ix86). L. -- Luca Berra -- bluca@comedia.it Communication Media & Services S.r.l. /"\ \ / ASCII RIBBON CAMPAIGN X AGAINST HTML MAIL / \