----- Original Message -----
> From: "Mark Phippard" <markphip_at_gmail.com>
> To: "amartin" <amartin_at_xes-inc.com>
> Cc: "users" <users_at_subversion.apache.org>
> Sent: Tuesday, December 13, 2016 3:35:37 PM
> Subject: Re: Backup using ZFS Snapshots
> On Tue, Dec 13, 2016 at 4:17 PM, Andrew Martin <amartin_at_xes-inc.com> wrote:
>
>> Hello,
>>
>> I am running a Subversion 1.9.3 server on Ubuntu 16.04. I currently use
>> svnadmin hotcopy to safely backup the SVN repositories, but since the
>> repositories are now hosted on a ZFS dataset, I would like to utilize ZFS's
>> snapshot capabilities to create atomic, point-in-time backups of the
>> repositories. My plan to do this is as follows:
>>
>> 1. create zfs snapshot
>> 2. clone zfs snapshot and mount at a temporary location
>> 3. run svnadmin hotcopy from the mounted clone to safely create a backup
>> 4. umount and destroy clone
>>
>> My only concern is if a commit is in-progress when the zfs snapshot occurs,
>> would svnadmin hotcopy still be able to safely handle creating the backup?
>>
>
> svnadmin hotcopy will not have a problem with an in-process commit. That
> is kind of one of the points of that command.
>
>
>
>> Is this a safe procedure for creating backups?
>>
>
> I know very little about ZFS but I do not understand why you would do
> this. If it can take snapshots, then why wouldn't you just take a snapshot
> of the actual live repository, why would you want to copy it?
>
> Setting that aside, I think hotcopy is a very good way to do backups ...
> but it is not clear what value would come from taking a snapshot of the
> backup given that version control history is immutable etc. Also, once you
> create the initial hotcopy, you can use the hotcopy --incremental option to
> just copy the newer revisions. Do that from a post-commit hook and you can
> always have a backup up to the latest commit.
>
> To me snapshots would seem like a way to do backups without using hotcopy.
> I am not sure the value of combining the two ... but it should work
> technically if you have "reasons".
>
> Mark
The reason I want to do it this way is that I want to "pull" the backups to
the backup server rather than "pushing" them from the Subversion server. In
order to do that, I plan on mounting the clone over NFS on the backup server
and then using "svnadmin hotcopy" to pull any new data onto the backup server.
Yes, I could just mount the live repository, but I have a number of repositories
to backup and using the ZFS snapshot ensures that they are all from a single
point-in-time.
It sounds like "svnadmin hotcopy" will just ignore any in-progress commit, so
even if the ZFS snapshot happened in the middle of a commit, it would still
result in a consistent backup.
Thanks,
Andrew
Received on 2016-12-13 22:48:04 CET