>>>>> On Sun, 12 Oct 2008 11:21:12 -0400, Dan Langille said: > > With incremental and differential backups, the goal is a list of files > that have changed since a given point in time. Traditionally, this > list is obtained by using find (AFAIK). On filesystems with large > numbers of files,the list creation can take considerable time. How can > we improve the performance of this stage? > > For some time, I have wanted the filesystem (or OS) to give me a list of > files changed since time X. I've just heard Pawel Jakub Dawidek speak > at NYCBSDCon about ZFS. I asked him if he thought getting such a list > was possible. He suggested it may be. Strategy: ZFS is able to return > a file name given a particular block. That is, if you know a particular > block has changed, ZFS will tell you what file it belongs to. > > When using ZFS snapshots, the system keeps a list of blocks that have > changed since the last snapshot. It may be feasible to traverse this > list of block to obtain the list of files required by Bacula. > > My thoughts: > > 1 - I'm not proposing to apply this strategy to Bacula internally. > However, an external script would be very useful. Bacula already > provides a mechanism for a FileSet to be specified by an external > script. I'm thinking: combine the two approaches to provide faster > incremental/differential backups. > > 2 - This strategy may be applicable to other filesystems that provide > similar mechanisms (list of blocks changed, getting file names for those > blocks). It was suggested during the talk that auditing, etc may > provide the needed hooks.
A similar idea is used by Apple to implement Time Machine. __Martin ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Bacula-devel mailing list Bacula-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-devel
