From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (mx1.redhat.com [172.16.48.31]) by int-mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id j9KCKSV19943 for ; Thu, 20 Oct 2005 08:20:28 -0400 Received: from eproxy.vsaa.lv (eproxy.vsaa.lv [81.198.191.140]) by mx1.redhat.com (8.12.11/8.12.11) with ESMTP id j9KCKQ9V019864 for ; Thu, 20 Oct 2005 08:20:26 -0400 Message-ID: <43578B7E.7060805@hq.vsaa.lv> Date: Thu, 20 Oct 2005 15:20:14 +0300 From: Rich MIME-Version: 1.0 Subject: Re: [linux-lvm] xfs_freeze & lvm2 Content-Transfer-Encoding: 7bit Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: linux-lvm@redhat.com i'm sorry for breaking the thread, but i am reading responses through web archive ;) .. >> as i understand it, consistent copy is created when lvcreate is >> issued, not when snapshot volume is mounted - is this right ? > As i understood things, no. Mounttime matters ;-) see > and as example . well, supposedly there is no way to see wether changes are propogated to snapshot between lvcreate and mount because you must mount it to see (reminds about cats & boxes) ;) but there are two things that lead me to believe it is lvcreate that matters : 1. "You should remove snapshot volume when you have finished with them because they take a copy of all data written to the original volume and this can hurt performance." note, it says "remove", not unmount. additionally, you can easily mount and unmount snapshot several times - it would be pretty hard to have a consistent copy in such a case; 2. i did some testing before : created a snapshot (but did not mount it), made some modifications to original data and checked wether used space would increase for snapshot volume (with lvdisplay). well, it did - so i assumed snapshot is created, well, when it is created :) .. >> if it actually is done together with snapshot, does this mean that i >> really can forget about xfs_freeze and just create snapshots ? well, what about this part ? from what i have read here and also in other places, xfs filesystem should be consistent, but i would like to be sure (though i might try to test this by simulating activity during lvcreate, i would prefer not to) >> must i specify ro in mount options or is this optional ? > Well, if i'm wrong ( and to be honest, i didn't play around with all > the stuff for 1 1/2 years now :-( ) somebody might correct me, but if > i remember postings from linux-xfs mailing list, rw-snapshots with XFS > is not quite unstable ... well, as i don't need r/w anyway, i'll stick with ro, just to be sure then :) > Cheers > Klaus -- Rich