Peter, That's a great suggestion. And as fortune would have it, we have the code to do it already. Scrubbing in ZFS is driven from the logical layer, not the physical layer. When you scrub a pool, you're really just scrubbing the pool-wide metadata, then scrubbing each filesystem.
At 50,000 feet, it's as simple as adding a zfs(1M) scrub subcommand and having it invoke the already-existing DMU traverse interface. Closer to ground, there are a few details to work out -- we need an option to specify whether to include snapshots, whether to descend recursively (in the case of nested filesystems), and how to handle branch points (which are created by clones). Plus we need some way to name the MOS (meta-object set, which is where we keep all pool metadata) so you can ask to scrub only that. Sounds like a nice tidy project for a summer intern! Jeff On Sat, Mar 29, 2008 at 05:14:20PM +0000, Peter Tribble wrote: > A brief search didn't show anything relevant, so here > goes: > > Would it be feasible to support a scrub per-filesystem > rather than per-pool? > > The reason is that on a large system, a scrub of a pool can > take excessively long (and, indeed, may never complete). > Running a scrub on each filesystem allows it to be broken > up into smaller chunks, which would be much easier to > arrange. (For example, I could scrub one filesystem a > night and not have it run into working hours.) > > Another reason might be that I have both busy and > quiet filesystems. For the busy ones, they're regularly > backed up, and the data regularly read anyway; for the > quiet ones they're neither read nor backed up, so it > would be nice to be able to validate those. > > -- > -Peter Tribble > http://www.petertribble.co.uk/ - http://ptribble.blogspot.com/ > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
