On Fri, Oct 06, 2006 at 12:02:16PM -0700, Matthew Ahrens wrote: > In my opinion, the marginal benefit of per-write(2) versions over > snapshots (which can be per-transaction, ie. every ~5 seconds) does not > outweigh the complexity of implementation and use/administration.
Per-write(2) versions would be worse than useless in many, if not most cases. Even per-close(2) versions wouldn't always be useful. Versions need to be captured / snapshots need to be taken when it makes sense given what the application/user is doing. Versioning cannot be automated; taking periodic snapshots != capturing application state. FS-wide snapshots make a lot of sense in general, and can serve as a basic versioning tool for filesystems that have very specific uses (e.g., for a database). Per-file snapshots (versions, whatever) make sense more generally, but need to be used by applications/users that are aware of them, else the feature would go unused or, worse, it'd be worse than useless. IMO, there's no urgent need for any new features around this, but if there is a need, then it's for snapshots that aren't filesystem-wide, with APIs so that applications can be aware of it. Nico -- _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
