On Tue, 2009-07-07 at 17:42 -0700, Richard Elling wrote: > Christian Auby wrote: > > ZFS is able to detect corruption thanks to checksumming, but for single > > drives (regular folk-pcs) it doesn't help much unless it can correct them. > > I've been searching and can't find anything on the topic, so here goes: > > > > 1. Can ZFS do parity data on a single drive? e.g. x% parity for all writes, > > recover on checksum error. > > 2. If not, why not? I imagine it would have been a killer feature. > > > > I guess you could possibly do it by partitioning the single drive and > > running raidz(2) on the partitions, but that would lose you way more space > > than e.g. 10%. Also not practical for OS drive. > > > > You are describing the copies parameter. It really helps to describe > it in pictures, rather than words. So I did that. > http://blogs.sun.com/relling/entry/zfs_copies_and_data_protection > -- richard
I think one solution to what Christian is asking is copies. But I think he is asking if there is a way to do something like a 'raid' of the block so that your capacity isn't cut in half. For example, write 5 blocks to the disk, 4 data and one parity, then if any one of the block gets corrupted or is unreadable, then you can reconstruct the missing block. In this example you would only loose 20% of your capacity not 50%. I think this option would only really be useful for home users or simple workstations. It also could have some performance implications. -Jebnor -- Louis-Frédéric Feuillette <jeb...@gmail.com> _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
