[ovirt-users] Can't remove snapshot due to low disk space on storage domain?

Rik Theys Rik.Theys at esat.kuleuven.be
Wed Feb 11 08:06:35 EST 2015


Hi,

OK since my hosts are still CentOS 6.6, I will schedule downtime.

Will removing it this way also require the additional disk space in the 
storage domain?

Rik


On 02/11/2015 02:03 PM, Elad Ben Aharon wrote:
> Indeed, removing the disk snapshot from the 'Disk Snapshots' subtab will
> remove only the snapshot of the disk, not the disk itself.
> Regarding snapshot removal while the  VM is running - this feature is
> pretty new (live snapshot merge). AFAIK, this feature is tech preview
> for 3.5. It also depends on the OS you're using on the hosts. RHEL 7.1
> supports it, but again, as tech preview.
> Therefore, the safest way to remove the snapshot of the disk would be to
> do it while the VM is not running.
>
>
> ------------------------------------------------------------------------
> *From: *"Rik Theys" <Rik.Theys at esat.kuleuven.be>
> *To: *"Elad Ben Aharon" <ebenahar at redhat.com>
> *Cc: *users at ovirt.org
> *Sent: *Wednesday, 11 February, 2015 2:44:55 PM
> *Subject: *Re: [ovirt-users] Can't remove snapshot due to low disk
> space        on storage domain?
>
> Hi,
>
> I created the snapshot on the Snapshots subtab of the Virtual machines
> tab. I did this when my engine (and host) was running oVirt 3.4. It
> is/was a snapshot of the entire VM (I deselected the memory state).
>
> I since upgraded the engine to 3.5.
>
> When I look at the snapshots subtab of the virtual machine, I see the
> Current snapshot which is "Active VM" and the snapshot I created before.
> This snapshot is a snapshot of both the OS and data disk.
>
> I can not delete the second snapshot when the VM is running. If I power
> down the VM, I can't remove the snapshot as it brings up the error I
> mentioned before.
>
> However, when I look at the disk snapshots subtab of the storage tab
> (like you suggested), I see both disks with a snapshot and I can select
> "Remove" there while the VM is running. Is it safe to remove them this
> way? This will only remove the snapshot and not the disk (and data) from
> my (running) VM?
>
> Regards,
>
> Rik
>
>
> On 02/11/2015 01:26 PM, Elad Ben Aharon wrote:
>  > I'm not sure I understand which RHEV version you're using now.
>  > If you're using RHEV 3.5, it is possible to remove a snapshot of a
>  > single disk.
>  > You can do it via webadmin, Under the 'Disks Snapshots' subtab of the
>  > relevant storage domain, in the 'Storage' main tab.
>  >
>  > As for your second question, the free space has to be in the same
>  > storage domain.
>  > ------------------------------------------------------------------------
>  > *From: *"Rik Theys" <Rik.Theys at esat.kuleuven.be>
>  > *To: *"Elad Ben Aharon" <ebenahar at redhat.com>
>  > *Cc: *users at ovirt.org
>  > *Sent: *Wednesday, 11 February, 2015 2:10:13 PM
>  > *Subject: *Re: [ovirt-users] Can't remove snapshot due to low disk
>  > space        on storage domain?
>  >
>  > Hi,
>  >
>  > Thats unfortunate :-(. It would have been great if oVirt told me during
>  > the creation of the snapshot that I would be unable to remove it later
>  > due to unsufficient free space in the storage domain :-).
>  >
>  > The VM has two disks - a small and a large one - so the snapshot
>  > contains both. Can I still remove the large disk while it has snapshots?
>  >
>  > Luckily the used disk space in the (preallocated) large disk is low
>  > enough so I can fit it on another temporary disk then.
>  >
>  > Does the free space have to be in the same storage domain, or can oVirt
>  > use another storage domain for the temporary volume? IOW, can I add an
>  > NFS storage domain which oVirt can use to create the temporary disk on?
>  >
>  > Regards,
>  >
>  > Rik
>  >
>  >
>  > On 02/11/2015 12:57 PM, Elad Ben Aharon wrote:
>  >  > *equals or larger than the disk size
>  >  >
>  >  >
> ------------------------------------------------------------------------
>  >  > *From: *"Elad Ben Aharon" <ebenahar at redhat.com>
>  >  > *To: *"Rik Theys" <Rik.Theys at esat.kuleuven.be>
>  >  > *Cc: *users at ovirt.org
>  >  > *Sent: *Wednesday, 11 February, 2015 12:18:35 PM
>  >  > *Subject: *Re: [ovirt-users] Can't remove snapshot due to low disk
>  >  > space        on        storage domain?
>  >  >
>  >  > Snapshot removal (merge) includes a create volume phase. This
> volume is
>  >  > temporary and gets removed once the snapshot merge is completed. Its
>  >  > size is the size of the disk.
>  >  > That means that in order to remove the snapshot, the storage domain
>  >  > should have available size that is equal to the disk size.
>  >  >
>  >  >
>  >  >
>  >  >
>  >  >
>  >  >
>  >  >
>  >  >
>  >  >
>  >  > Elad Ben Aharon
>  >  > RHEV-QE storage
>  >  >
>  >  >
>  >  >
> ------------------------------------------------------------------------
>  >  > *From: *"Rik Theys" <Rik.Theys at esat.kuleuven.be>
>  >  > *To: *users at ovirt.org
>  >  > *Sent: *Tuesday, 10 February, 2015 12:00:10 PM
>  >  > *Subject: *[ovirt-users] Can't remove snapshot due to low disk space
>  >  > on        storage domain?
>  >  >
>  >  > Hi,
>  >  >
>  >  > I'm running the ovirt engine 3.4 series. I've created a snapshot
> of a VM
>  >  > with an OS and data disk before upgrading the machine.
>  >  >
>  >  > The upgrade went fine and I now want to remove the snapshot.
>  >  > Unfortunately this fails with the error:
>  >  >
>  >  > "Cannot remove Snapshot. Low disk space on target Storage Domain
>  >  > stadius-virt2_PERC."
>  >  >
>  >  > So I can't free disk space by removing the snapshot because I
> don't have
>  >  > enough space?
>  >  >
>  >  > When I look at the VM the disks are shown as preallocated (which
> is what
>  >  > I selected during installation). When I look at the storage tab
> and list
>  >  > the disks in my storage domain, the disks are now shown as thin
>  >  > provisioned with the actual size > virtual size.
>  >  >
>  >  > How can I remove this snapshot? I don't have enough free disk space in
>  >  > my storage domain to duplicate the data disk of my VM.
>  >  >
>  >  > Regards,
>  >  >
>  >  > Rik
>  >  >
>  >  >
>  >  > --
>  >  > Rik Theys
>  >  > System Engineer
>  >  > KU Leuven - Dept. Elektrotechniek (ESAT)
>  >  > Kasteelpark Arenberg 10 bus 2440  - B-3001 Leuven-Heverlee
>  >  > +32(0)16/32.11.07
>  >  > ----------------------------------------------------------------
>  >  > <<Any errors in spelling, tact or fact are transmission errors>>
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>  >
>  >
>  > --
>  > Rik Theys
>  > System Engineer
>  > KU Leuven - Dept. Elektrotechniek (ESAT)
>  > Kasteelpark Arenberg 10 bus 2440  - B-3001 Leuven-Heverlee
>  > +32(0)16/32.11.07
>  > ----------------------------------------------------------------
>  > <<Any errors in spelling, tact or fact are transmission errors>>
>  >
>
>
> --
> Rik Theys
> System Engineer
> KU Leuven - Dept. Elektrotechniek (ESAT)
> Kasteelpark Arenberg 10 bus 2440  - B-3001 Leuven-Heverlee
> +32(0)16/32.11.07
> ----------------------------------------------------------------
> <<Any errors in spelling, tact or fact are transmission errors>>
>


-- 
Rik Theys
System Engineer
KU Leuven - Dept. Elektrotechniek (ESAT)
Kasteelpark Arenberg 10 bus 2440  - B-3001 Leuven-Heverlee
+32(0)16/32.11.07
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<<Any errors in spelling, tact or fact are transmission errors>>


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