On 08/08/2012 07:38 AM, Philip Martin wrote: > I've been asked about using operating system snapshots to make backups > of live repositories. These could be filesytem snapshots like ZFS or > FreeBSD's UFS2, or block level snapshots like Linux's LVM, or maybe even > a Windows shadow copy. The reasons for using snapshots, rather than > "svnadmin hotcopy", are that it's a better fit with the overall backup > strategy or that it is faster or requires less disk space or less IO. > This has also been discussed on the mailing lists, e.g. > http://svn.haxx.se/users/archive-2012-02/0233.shtml > As far as I know the snapshot method should work provided there are no > bugs in Subversion or the snapshot code but it would be good to have > more confidence that it works. > > One of our customers asked about locking the FSFS write-lock file before > taking the snapshot as this would halt writes and make the repository > quiescent. It's certainly possible to do it, I wrote a program that > calls the private API svn_fs_fs__with_write_lock, but calling a private > API is a hack and I need to lock the rep-cache as well. > > So I was wondering whether we should introduce a public API to do this > properly either at the svn_fs_ or svn_repos_ level. For FSFS this would > stop writes while allowing reads. A BDB implementation would probably > stop reads as well.
This seems reasonable. I can envision the likes of an svn_fs_freeze()/svn_fs_unfreeze() API pair, with svn_repos_* flavors thereof for adding hook support. -- C. Michael Pilato <cmpil...@collab.net> CollabNet <> www.collab.net <> Enterprise Cloud Development
signature.asc
Description: OpenPGP digital signature
