zfs code - Apr 2009 - ZFS SMI vs EFI performance using filebench

I have been testing the performance of zfs vs. ufs using filebench.  The setup
is a v240, 4GB RAM, 2 at 1503MHz, 1 320GB _SAN_ attached LUN, and using a ZFS
mirrored root disk.  Our SAN is a top notch NVRAM based SAN.  There are lots of
discussions using ZFS with SAN based storage.. and it seems ZFS is designed to
perform best with dumb disk (JBODs).  The test I ran support this observation..
and no matter what kernel tunables I make the zfs_params, I just can''t
seem to get the performance from ZFS that I can get out of UFS under the Solaris
Volume Manager (SVM). I am using the single LUN test because it performed better
than any striping configuration I came up with. We don''t use any
software RAID of any kind.. because the SAN does it all for us.   One
interesting test revealed better performance using the SMI label on our LUNs
than that EFI label.  This is true for using the fileserver, 
large_db_oltp_8k_uncached, and large_db_oltp_8k_cached workloads from filebench.
The fileserver differences were not that great, but he db workloads performed 4x
better using the SMI labeled LUNs as opposed to the EFI labeled LUNs.  Does
anyone know why ZFS would perform better with the SMI labeled luns that the EFI
labeled luns?  Is this the way it suppose to be? Thanks.
-- 
This message posted from opensolaris.org

(zfs-discuss would be a better forum for this than zfs-code)

You don''t mention what release you''re running, but before
6532509
(which was integrated in s10u6) partitions on EFI labeled disks started
on block 34, which could account for it.

-  Eric
-- 
This message posted from opensolaris.org