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Re: Question about instance volumes


Hi,

so if volume was created from template (VM from template), then it should
have a golder/baking image for sure, I find it impossible that it doesn't
have it.
If you deploy VM with ISO file (blank volume, attach ISO, install OS...)
then it should be brand new file, no baking file attached.
As for the baking file disappearing, I hear this first time - but I do know
that for some storage (SolidFire at least, but perhaps similar with
NFS/CEPH) if you delete all VMs (thus all child images of a parent/golden
image), than garbage collector will also remove the parent/golden image on
storage.

Hope that helps.

Andrija

On 23 April 2018 at 15:50, Felipe Arturo Polanco <felipeapolanco@xxxxxxxxx>
wrote:

> Thanks for the answer.
>
> May I ask why are there some instances that do have a golden image and some
> that do not?
>
> All the instances come from a template so I wonder why this varies.
>
> Also why would the golden image be deleted by the Cloudstack scavenger? I
> have an Instance failing to boot because it's backing file was deleted by
> the scavenger.
>
> Thanks,
>
> On Mon, Apr 23, 2018 at 4:43 AM, Andrija Panic <andrija.panic@xxxxxxxxx>
> wrote:
>
> > As Ivan explained, when there is brand new template used, ACS will copy
> it
> > from Secondary Storage to Primary Storage, this image will become
> "parent"
> > / backing / gold image, and is locked as Read Only. Any new VM will have
> > it's volume "linked" as child image to this parent image.
> > This is done to
> >
> > 1) Save space (imagine 100GB template), and you deploy 100 VMs = maybe
> > 101GB totally used really...(until you write some new data - it is
> written
> > to child images) vs 10000GB if it would be separate images.
> >
> > 2) This also brings some performance benefits, since you read from 1 x
> > 100GB image, not from 100x 100GB images...
> >
> > Cheers
> >
> >
> > On 23 April 2018 at 03:59, Ivan Kudryavtsev <kudryavtsev_ia@xxxxxxxxx>
> > wrote:
> >
> > > Hi.
> > >
> > > When you create a VM from a template then ACS doesn't copy the template
> > to
> > > a new root image, but creates it thin, pointing the volume to the
> > template
> > > as a backing store device.
> > >
> > > пн, 23 апр. 2018 г., 8:16 Felipe Arturo Polanco <
> > felipeapolanco@xxxxxxxxx
> > > >:
> > >
> > > > Hello,
> > > >
> > > > I am seeing a behavior that I would like to ask about.
> > > >
> > > > I have some instances that instead of having a normal qcow2 disk
> file,
> > > have
> > > > a qcow2 file that points to another backing store file.
> > > >
> > > > eg:
> > > >
> > > > <disk type='file' device='disk'>
> > > >       <driver name='qemu' type='qcow2' cache='none'/>
> > > >       <source file='/mnt/ps4/c6a79f0b-60b2-419c-98af-6ae854f88ad1'/>
> > > >       <backingStore type='file' index='1'>
> > > >         <format type='raw'/>
> > > >         <source file='/mnt/ps4/ddc78c68-47b2-
> 43ef-9109-4c91ebb8bda5'/>
> > > >         <backingStore/>
> > > >       </backingStore>
> > > >       <target dev='vda' bus='virtio'/>
> > > >       <serial>c6a79f0b60b2419c98af</serial>
> > > >       <alias name='virtio-disk0'/>
> > > >       <address type='pci' domain='0x0000' bus='0x00' slot='0x04'
> > > > function='0x0'/>
> > > >     </disk>
> > > >
> > > > I am reading online that this is seen when there is a snapshot of
> > another
> > > > disk file, but I have no snapshots, just a regular Linux server that
> I
> > > > created through the Cloudstack UI.
> > > >
> > > > Any idea of why this would happen? Not all Instances have this
> backing
> > > > storage file.
> > > >
> > > > Thanks,
> > > >
> > >
> >
> >
> >
> > --
> >
> > Andrija Panić
> >
>



-- 

Andrija Panić