If you issue aligned, full-record write requests, there is a definite advantage to continuing to set the record size. It allows ZFS to process the write without the read-modify-write cycle that would be required for the default 128K record size. (While compression results in records of variable physical length, it's the logical length which is important here, since it determines whether part of an on-disk block needs to be read before the block can be rewritten.)
Two notes -- First, the version of ZFS in the initial S10U2 release can perform the read-modify-write even if the record size matches. This is fixed in later OpenSolaris builds, I'm not sure if it's been patched back yet. Second, I believe the eventual goal is for ZFS to detect when a smaller record size would be advantageous, but this has not yet been done. This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
