comment from anthony on the review request. "
This srcipt is not used for XS 6.2 + SP1 + FOX and above, vdi.copy is used instead. it is good to have this fix though. " ~Rajani On Wed, Feb 18, 2015 at 9:16 PM, Remi Bergsma <rberg...@schubergphilis.com> wrote: > Hi, > > This summer we had some serious issues with creating snapshots on > XenServer, see CLOUDSTACK-7319 for details. Long story short, to copy the > ‘dd’ command was used and that hammered dom0 until it would crash/fence. > The script that did the copy at the time was vmopsSnapshot. We added two > flags: iflag=direct and oflag=direct. Problem solved from 4.4.0 and on > you’d expect. > > We just had a hypervisor crashing due to heavy dd load again. Eventually, > it could not reach the storage any more so it fenced. When investigating, > we found that the copy is now done again without the direct flags. The > reason is that the script has been removed and that a xapi plugin is now > used instead. Problem is that this does not use the direct flags :-s So our > issue is back. > > /etc/xapi.d/plugins/copy: > def dd_vdi__(src_dev, dest_dev): > os.system('dd if=/dev/%s of=/dev/%s bs=2M' % (src_dev, dest_dev)) > > We will be hot fixing all hypervisors and add the flags asap. > > This happens from 4.4 and on if you’re using XenServer 6.2.5 (which is > 6.2.0 with patch XS62ESP1004). If you run this XenServer version, I’d patch > the copy script asap. > > Regards, > Remi > > > > > > > > > >