Looks like I have mistaken your settings for dedup=fletcher4,verify. Dedup=on gives you strong checksumming, so the reason behind your problems is something different.
Regards, Andrey On Wed, Dec 16, 2009 at 8:19 PM, Chris Murray <chrismurra...@gmail.com> wrote: > So if the ZFS checksum is set to fletcher4 at the pool level, and > dedup=on, which checksum will it be using? > > If I attempt to set dedup=fletcher4, I do indeed get this: > > cannot set property for 'zp': 'dedup' must be one of 'on | off | verify > | sha256[,verify]' > > Could it be that my performance troubles are due to the calculation of > two different checksums? > > Thanks, > Chris > > -----Original Message----- > From: cyril.pli...@gmail.com [mailto:cyril.pli...@gmail.com] On Behalf > Of Cyril Plisko > Sent: 16 December 2009 17:09 > To: Andrey Kuzmin > Cc: Chris Murray; zfs-discuss@opensolaris.org > Subject: Re: [zfs-discuss] Troubleshooting dedup performance > >>> I've set dedup to what I believe are the least resource-intensive >>> settings - "checksum=fletcher4" on the pool, & "dedup=on" rather than >> >> I believe checksum=fletcher4 is acceptable in dedup=verify mode only. >> What you're doing is seemingly deduplication with weak checksum w/o >> verification. > > I think fletcher4 use for the deduplication purposes was disabled [1] > at all, right before build 129 cut. > > > [1] > http://hg.genunix.org/onnv-gate.hg/diff/93c7076216f6/usr/src/common/zfs/ > zfs_prop.c > > > -- > Regards, > Cyril > > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
