hi i'm currently doing the following: every night (when there's not much i/o on the server), i create a snapshot of one LV. the next day i remove this snapshot, and create another one. this worked without problems so far. a couple of months back i tried to create more than one snapshot of one LV, and it didn't work out. it hang, got a kernel panic, whatever. i would like to try again with multiple snapshots (i don't plan to use those snapshots, it's only for backup, if something gets deleted from the original LV, i mount the last snapshot read-only, and get the files from it). has there anything changed since? Steffen Plotner wrote: > Hello, > > On an experimental system I changed the device mapper from 1.01.02 to 1.02.02 and lvm from 2.01.08 to 2.02.01 and upgraded on FC4 from 2.6.13 to 2.6.14-1.1653_FC4. Create a LV, create a snapshot, dd if=/dev/zero of=test bs=1M count=10000 on the LV (not the snapshot), then try to remove the snapshot and the kernel faults. > > I suspect that the outstanding block I/Os are probably the issue. You ask about the 5 second outage of ietd? the iscsi initiators see the event and reconnect - as long as the outage is not more than 1 minute (windows does not like it, linux is very resilient about it). > > Steffen > > ________________________________ > Steffen Plotner > Systems Administrator/Programmer > Systems & Networking > Amherst College > PO BOX 5000 > Amherst, MA 01002-5000 > Tel (413) 542-2348 > Fax (413) 542-2626 > Email: swplotner@amherst.edu > ________________________________ > > ________________________________ > > From: linux-lvm-bounces@redhat.com on behalf of Ming Zhang > Sent: Wed 2/1/2006 3:54 PM > To: LVM general discussion and development > Subject: RE: 'snapshot' target still experimental :-( > > > > i can confirm this. iet runs well with heavy io until you create many > snapshots. lvresize will be slow as well, though not hang. i think that > is because the outstanding bio? not quite since i faced that several > months ago. > > ps, not lvm related, but if u stop iet for 5 seconds. i guess iscsi ini > will be unhappy? :P we can discuss in iet list. > > ming > > > On Wed, 2006-02-01 at 13:39 -0500, Steffen Plotner wrote: >> Hi, >> >> I apologize for looking up your machine. I have reported this problem >> sometime ago in November of last year. >> >> https://www.redhat.com/archives/linux-lvm/2005-November/msg00044.html >> >> We currently deployed an iscsi-target (from sourceforge) server on FC4 >> which functions well, until we utilize snapshots. The way I currently >> remove snapshots is to stop the iscsi-target daemon for 5 seconds, to >> let everything settle, then remove the snap, the restart the >> iscsi-target and all is ok (of course this is not how I would like to do >> things.. :). >> >> I have tried several patches dm and lvm in late December and they did >> not help. I have specifics at my house. I will email those later on. >> Thank you for responding to this issue. >> >> Steffen >> >> -----Original Message----- >> From: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com] >> On Behalf Of Alasdair G Kergon >> Sent: Wednesday, February 01, 2006 1:31 PM >> To: LVM general discussion and development >> Subject: Re: 'snapshot' target still experimental :-( >> >> On Wed, Feb 01, 2006 at 01:07:20PM -0500, Steffen Plotner wrote: >>> cd to a directory on an lv that has an active snapshot dd if=/dev/zero >>> of=test bs=1M count=10000 >>> And see how hard it is to remove a live active snapshot. >> Strange - I don't recall anyone reporting that problem before. >> >> I've just tried it here and the machine locked up:-( >> >> Alasdair >> -- >> agk@redhat.com >> >> _______________________________________________ >> linux-lvm mailing list >> linux-lvm@redhat.com >> https://www.redhat.com/mailman/listinfo/linux-lvm >> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ >> >> _______________________________________________ >> linux-lvm mailing list >> linux-lvm@redhat.com >> https://www.redhat.com/mailman/listinfo/linux-lvm >> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ > > _______________________________________________ > linux-lvm mailing list > linux-lvm@redhat.com > https://www.redhat.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > linux-lvm mailing list > linux-lvm@redhat.com > https://www.redhat.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
