Restoring and snapshots
dpchrist at holgerdanske.com
Sun Apr 12 21:09:55 UTC 2020
On 2020-04-10 02:30, Andrea Venturoli wrote:
> When I'm doing backups/dumps of ZFS filesystems (with whatever tool),
> I use snapshots. So, suppose I have the following datasets: /etc /usr
> /usr/local /var
> I'll snapshot them and back up /etc/.zfs/snapshot/snapname/
> /usr/.zfs/snapshot/snapname/ /usr/local/.zfs/snapshot/snapname/
> Then I'll get the same directory structure when restoring. Any idea
> how to easily remove the .zfs/snap and go back to the original tree?
> I tried writing a few lines of script, but I found out that's not so
> easy (due to directories which must overlap, spaces in file names,
> Any hint?
On 2020-04-11 01:31, Andrea Venturoli wrote:
> I'm wondering if I should abandon sh and use something else
On 2020-04-12 01:50, Andrea Venturoli wrote:
> On 2020-04-12 10:23, David Christensen wrote:
>> It sounds like you are using file- and directory-level backup tools
>> for ZFS filesystems (?).
> Exactly. As I said, however, I'm having the same problem with UFS...
> You are focusing on ZFS, but this was not the point of the original
> post; it was just an example.
>> If you are using file- and directory-level backup tools to back up
>> ZFS snapshots, that definitely sounds like you are barking up the
>> wrong tree.
> Sometimes you have complex system, with several machines (some with
> ZFS, some with UFS, some with a mix and some not even BSD) and you
> need an integrated solution. Handling ZFS filesystem differently from
> the others would be a pain. Besides, restoring a whole filesystem if
> you just need a couple of files would be very inefficient.
I do not use Bacula and have only a basic understanding of it.
Beware that "integrated solution" can mean "all your eggs in one basket".
That said, two ideas come to mind:
1. It appears Bacula provides a plug-in API. So, write a plug-in for
Bacula that knows how to convert Bacula backup saved paths to client
filesystem live paths (and vice-versa?) when the former are ZFS snapshots.
2. Have Bacula restore a set of related ZFS snapshots into a temporary
directory and then write a script that reassembles everything.
A key parameter in any case will be the ZFS 'mountpoint' property for
the ZFS snapshots in question. I don't know if Bacula preserves ZFS
properties on backup or restore. If not, this information must come
from somewhere else.
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