----- Original Message ----- > From: "Mark Phippard" <markp...@gmail.com> > To: "amartin" <amar...@xes-inc.com> > Cc: "users" <users@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 <amar...@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
