On Mar 5, 2010, at 5:10 PM, James Dickens wrote: > On Fri, Mar 5, 2010 at 4:48 PM, Tonmaus <sequoiamo...@gmx.net> wrote: > Hi, > > so, what would be a critical test size in your opinion? Are there any other > side conditions? > > > when your dedup hash table ( a table that holds a checksum of every block > seen on filesystems/zvols after dedup was enabled) exceeds memory, your > performance degrades exponentially probably before that.
More important is the small, random I/O performance of your pool. For fast devices, like 15krpm disks, SSDs, or array controllers with nonvolatile caches, performance should be good. For big, slow JBOD drives, the small, random I/O performance is poor and you pay for that cost savings with time spent waiting. -- richard ZFS storage and performance consulting at http://www.RichardElling.com ZFS training on deduplication, NexentaStor, and NAS performance http://nexenta-atlanta.eventbrite.com (March 16-18, 2010) _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
