[OpenIndiana-discuss] retrieve individual files from snapshot of vbox virtual disc

[Harry Putnam]

Geoff Nordli <geoffn at gnaa.net> writes:

> On 14-12-24 01:36 PM, Harry Putnam wrote:
>> Build 151_a9
>> I have the time slider running on a zfs-fs that covers the area where my
>> virtual box guests live.
>>
>> I need some files from a gentoo linux guest.
>>
>> I have snaps of the vms OS v-discs.  How to get an individual file out of
>> there?
>>
>> Is there any way to get at the files in that vm virtual disc, or do I
>> have to make whole new gentoo vm and use the disc as one of that
>> guests disc.  That is, copy the snapshotted disc to a directory named
>> appropriately. Then create a new vm which uses that disc instead of
>> creating a new blank disk.
>>
>> Has anyone here done something like that?
>>
>> Before I make a really big mess of things I'd like to hear from
>> someone with a bit of experience on something like this?
>>
>> Maybe there is someway to mount it as loop-back mount on
>> openindiana?.  Its formated as linux ext4
>>
>>
>
>
> Hi Harry.
>
> Not sure if this is a zvol or a zfs filesystem.
>
> If it is a zvol, then I normally create a clone of snapshot and
> directly attach it to the running vbox guest (not on the same sata
> port as the existing disk).   You can attach the clone to the VM while
> the VM is running.

I'm not sure what a zvol is.  What I'm working with is one of several
zfs-fs on a zpool.

This attaching you speak of, again I don't know what you are talking
about there.  Where can I read up on that?

> Inside the guest, you can then mount it and retrieve the files you
> need to recover, you can then unmount it and remove the zvol from the
> running guest.

Sound great... but don't think is going to work here.

> If it is a zfs filesystem, then you should be able to directly access
> the snapshot using the hidden zfs directory.

Yes, of course I can access the snapshot directory and the snaps.  The
trouble is, the snap is of a virtual disc... I see no way to open the
disc.

I can't just add it to the vm to be mounted because its the same name
as one already there.  And the meta data kept by vbox is identical to
an existing disc.

Maybe there is some way to edit that meta data?  But all I can see is
to create a new vm and mount it with that.  Quite a lot of trouble to
get a single file. (In this particular case)

> Go to the root of the filesystem and cd .zfs/snapshot.  You will see
> the list of snapshots for the dataset.  You can then go in there and
> copy the files out.

No, what is in there is a virtual disc with linux fs on it, not loose
files.  It needs to be mounted somewhere.... but I see no way to mount
it on the virtual machine it comes from for the reasons above.