>From coalesce-leaf script: *Only LVM SRs will be considered, and only VDIs whose VHD chain length equals 2.* *Note that the VM will be suspended during the operation. DO NOT* *start/resume/unpause the VM during the operation.* * * So, I'm not sure this particular process will work with NFS based SRs.
Although i'm looking at the 5.5u2 version. On 15 November 2010 14:48, Simone Cariani <[email protected]> wrote: > Thank you very much for your reply!! I will follow your suggestions. > > > > Regards, > > > > Simone Cariani > > > > > > > > *Da:* Dave Scott [mailto:[email protected]] > *Inviato:* lunedì 15 novembre 2010 11.55 > *A:* 'Simone Cariani'; [email protected]; > [email protected] > *Oggetto:* RE: [Xen-API] problem with snapshot unallocation > > > > Hi Simone, > > > > Whenever you create a snapshot disk it will increase the length of the > “snapshot chain” by 1 and there is a hard length limit of 30. However > whenever you delete a snapshot disk the background “coalesce” process should > be able to reduce the “snapshot chain” length again. So your procedure > (create snapshot; export snapshot; delete snapshot) ought to work fine. This > is in fact the same process followed by the “VM protection and recovery” > feature which will be part of XCP 1.0. > > > > The problem you linked to is related but not quite the same: it refers to a > limitation within the “coalesce” process where it cannot reduce a chain of > length 2 into a chain of length 1. The only reason people worry about this > is because a chain of length 2 can take up a lot more space on LVM where > there is no “thin provisioning” – this isn’t a problem for you on NFS. > > > > Given your observation that this only happens to VMs with more than 1 > attached virtual disk, I think you’ve found a bug in the tool which you used > to add the second disk to the VM. When you delete a VM snapshot (or > uninstall a VM or template generally), only those disks which have a special > flag set are actually deleted (specifically those with > VBD.other-config:owner IIRC). If you use the “xe vm-disk-add” CLI command it > should set this flag. If this flag isn’t set then it would cause the > additional disks not to be deleted… this would cause your “snapshot chain” > to get ever bigger, hit 30 and then fail. > > > > I think a workaround is to identify the disk (VDI not VM) snapshots which > haven’t been deleted and delete them manually, possibly via the CLI (“xe > vdi-destroy”). After a short while the background “coalesce” process should > kick in and reduce your chain lengths again. > > > > Cheers, > > Dave > > > > _______________________________________________ > xen-api mailing list > [email protected] > http://lists.xensource.com/mailman/listinfo/xen-api > >
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