> From: Richard Elling [mailto:richard.ell...@gmail.com] > > On Oct 17, 2010, at 6:17 AM, Edward Ned Harvey wrote: > > >> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- > >> boun...@opensolaris.org] On Behalf Of Edward Ned Harvey > >> > >> If scrub is operating at a block-level (and I think it is), then how > >> can > >> checksum failures be mapped to file names? For example, this is a > >> long-requested feature of "zfs send" which is fundamentally > difficult > >> or > >> impossible to implement. > > > > How about that. I recently learned that "zfs diff" does exist > already, in > > b147 of openindiana. That means it's already in the oracle opened- > source > > zfs code, but apparently too new to be included in any of the present > > releases. > > > > So it seems, zfs does have some ability to figure out which file owns > a > > particular block on disk. > > uhm... of course this exists. The problem is that the efficient > mapping > goes the other way: files to blocks. Snapshots further complicate this > because a block may belong to a filename in one snapshot but the file > got renamed in another snapshot. Deduplication also complicates this > because a block may be referenced in multiple files. Maintaining this > mapping live is probably not worth the effort.
Thank you, but, the original question was whether a scrub would identify just corrupt blocks, or if it would be able to map corrupt blocks to a list of corrupt files. Until I wrote this comment about "zfs diff" no answer existed in this thread. (Unless I overlooked it somehow.) So thank you for the information about dedup and difficulty maintaining live information. Although it was irrelevant to the discussion at hand. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
