On Wed, July 11, 2012 04:50, Ferenc-Levente Juhos wrote: > Actually although as you pointed out that the chances to have an sha256 > collision is minimal, but still it can happen, that would mean > that the dedup algorithm discards a block that he thinks is a duplicate. > Probably it's anyway better to do a byte to byte comparison > if the hashes match to be sure that the blocks are really identical. > > The funny thing here is that ZFS tries to solve all sorts of data > integrity > issues with checksumming and healing, etc., > and on the other hand a hash collision in the dedup algorithm can cause > loss of data if wrongly configured. > > Anyway thanks that you have brought up the subject, now I know if I will > enable the dedup feature I must set it to sha256,verify.
There was a long-ish thread on the topic last year ("(Fletcher+Verification) versus (Sha256+No Verification) "): http://mail.opensolaris.org/pipermail/zfs-discuss/2011-January/thread.html#46864 _______________________________________________ zfs-discuss mailing list email@example.com http://mail.opensolaris.org/mailman/listinfo/zfs-discuss