On Sun, Jun 6, 2010 at 3:26 AM, Roy Sigurd Karlsbakk <r...@karlsbakk.net> wrote: > ----- "Brandon High" <bh...@freaks.com> skrev: >> Decreasing the block size increases the size of the dedup table >> (DDT). >> Every entry in the DDT uses somewhere around 250-270 bytes. > > Are you sure it's that high? I was told it's ~150 per block, or ~1,2GB per > terabytes of storage with only 128k blocks
No, that's the number that stuck in my head though. Even if the DDT entry is smaller, the point I was making doesn't change. A smaller record size will increase dedup performance at the cost of a larger DDT. Once the DDT is too large to fit in the ARC, performance tanks. -B -- Brandon High : bh...@freaks.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
