Hi, I am looking at doing LV cluster snapshots. I want to know if this is possible and what is the procedure. Thanks _________________________________________________________________ News, entertainment and everything you care about at Live.com. Get it now! http://www.live.com/getstarted.aspx _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On 6/13/2009 4:43 PM, Shirley Robles wrote:> Hi, > > I am looking at doing LV cluster snapshots. I want to know if this is > possible and what is the procedure.This has been a topic of discussion on the list multiple times. It seems that the general advice is if you can do backup using software inside of the guest domain, you should go that route and not try LVM. If you are using a LV as a physical device for a guest domain, you can do a snapshot of it in the host and take a backup of it. The problem is that if the device is mounted read-write in the guest domain, when you create the snapshot, you get a snapshot of a mounted volume. It would be in a state similar to if you had just destroyed the guest causing an unclean shutdown. In some cases, this state might still be useful. But in others, it would yield a backup that isn''t usable as not all of the data has been written to the volume. So if you have something that is critical or easily prone to data loss, I would recommend going another route. That all being said, if you still want to try doing this, you can use a procedure similar to this to do it. xm sysrq <guest> s # send a sysrq to the guest telling it to sync its disks. hopefully reducing problems on unclean volumes lvcreate -s -L 10GB -n guest-backup /path/to/guest/lv # create a snapshot mount /path/to/guest-backup /tmp/directory # mount the snapshot to a temporary directory. Some will say you should fsck before doing this. cd /tmp/directory tar jcvf /path/to/backup.tar.bz2 * # this is how I do a backup on mine, you can us other methods like rsync if you want cd # get out of the mounted volume umount /tmp/directory # unmountt the temporary snapshot lvremove -f /path/to/guest-backup # destroy the LV snapshot Hope that helps you out on this. Again, I recommend either using a method of backup from inside the guest or shutting down the guest during the backup. If you try this way, make sure you test restoring from backup on to another vm to make sure your data is intact. And I provide no warranty or guarantee on these direction. :) Good Luck _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Mike Lovell wrote:> On 6/13/2009 4:43 PM, Shirley Robles wrote: > > Hi, > > > > I am looking at doing LV cluster snapshots. I want to know if this is > > possible and what is the procedure. > > That all being said, if you still want to try doing this, you can use a > procedure similar to this to do it.i think the original question is about doing a snapshot (lvcreate -s) on a cluster shared storage (cLVM) until recently, the general answer was that it isn''t allowed. i don''t know if it''s still true, so (as always) the best advice is to test it first. Even if id does work, usually you won''t be able to do the snapshot from one node, and use either LV (original or snapshot) from another node. depending of how a Xen DomU accesses the LV, it might count as ''another node'', or it might be Dom0. and for backup, I wholeheartedly concur with Mike: it''s a lot safer to do it ''from inside'' the DomU. -- Javier _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hi, Thanks for the response. I have a cluster managed by OpenNebula, OpenNebula currently don''t support virtual images in other places than files, that is to say, don''t support LVM based virtual machines, this is for what I can not do domU Backups using LV. The idea of doing backups using software inside of the guest domain sounds interesting for me. Could you please give me some examples of software for backups inside of the guest domain. By Shutting down the guest during the backup, I would be interrupting the work of the user of the virtual machine, that is something I try to avoid. Regards _________________________________________________________________ News, entertainment and everything you care about at Live.com. Get it now! http://www.live.com/getstarted.aspx _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
There are plenty of backup systems out there. You could script it, or find a software solution for your DomU. You''d just be backing up the system like it was a regular server. Thank You, Nathan Eisenberg Sr. Systems Administrator Atlas Networks, LLC [cid:image001.gif@01C9EDEE.621A4D20] Atlas Networks<http://www.atlasnetworks.us/> is an Atlas Accelerator Company<http://www.atlasaccelerator.com/> From: xen-users-bounces@lists.xensource.com [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Shirley Robles Sent: Monday, June 15, 2009 4:26 PM To: xen-users@lists.xensource.com Cc: mike@dev-zero.net; javier@guerrag.com Subject: [Xen-users] cluster snapshots Hi, Thanks for the response. I have a cluster managed by OpenNebula, OpenNebula currently don''t support virtual images in other places than files, that is to say, don''t support LVM based virtual machines, this is for what I can not do domU Backups using LV. The idea of doing backups using software inside of the guest domain sounds interesting for me. Could you please give me some examples of software for backups inside of the guest domain. By Shutting down the guest during the backup, I would be interrupting the work of the user of the virtual machine, that is something I try to avoid. Regards ________________________________ Get news, entertainment and everything you care about at Live.com. Check it out!<http://www.live.com/getstarted.aspx%20> _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hi, I am wondering if doing backups from domU allow me to do the backup of the entire domU image and their content. Thanks From: nathan@atlasnetworks.us To: xen-users@lists.xensource.com Date: Mon, 15 Jun 2009 19:20:46 -0700 Subject: RE: [Xen-users] cluster snapshots There are plenty of backup systems out there. You could script it, or find a software solution for your DomU. You''d just be backing up the system like it was a regular server. Thank You, Nathan Eisenberg Sr. Systems Administrator Atlas Networks, LLC Atlas Networks is an Atlas Accelerator Company From: xen-users-bounces@lists.xensource.com [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Shirley Robles Sent: Monday, June 15, 2009 4:26 PM To: xen-users@lists.xensource.com Cc: mike@dev-zero.net; javier@guerrag.com Subject: [Xen-users] cluster snapshots Hi, Thanks for the response. I have a cluster managed by OpenNebula, OpenNebula currently don''t support virtual images in other places than files, that is to say, don''t support LVM based virtual machines, this is for what I can not do domU Backups using LV. The idea of doing backups using software inside of the guest domain sounds interesting for me. Could you please give me some examples of software for backups inside of the guest domain. By Shutting down the guest during the backup, I would be interrupting the work of the user of the virtual machine, that is something I try to avoid. Regards Get news, entertainment and everything you care about at Live.com. Check it out! _________________________________________________________________ News, entertainment and everything you care about at Live.com. Get it now! http://www.live.com/getstarted.aspx _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On 6/15/2009 9:19 PM, Shirley Robles wrote:> Hi, > > I am wondering if doing backups from domU allow me to do the backup of > the entire domU image and their content. > > ThanksYou should be able to back up the whole domU from within itself. At a previous job, one of the sys admins had things scripted to where there would be a rsync of the whole / file system to a rsync server. That is one option. mike _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users