Re: Orion: UFS vs ZFS testing questions

From: Martin Klier <>
Date: Thu, 06 Mar 2008 13:19:35 +0100
Message-ID: <>

Hi Michael,

Michael Schmitt schrieb:
> I have some questions about testing I did using the Orion tool against
> UFS and ZFS. We found that UFS was giving us better IOps results for
> small IO, while ZFS was giving us better MBps for large sequential IO.
> I was hoping that the list can help me figure out why. First, are there
> any issues using Orion to test these file systems?

maybe ZFS checksums and the internal transaction procedure / copy-on-write of ZFS kills your IOps performance. If you are able to read German, you might want to look up this papers.

Block checksums for each block are calculated and kept through all locations the block resides in, and checked at read time. The transaction system with copy-on-write causes multiple IOs per IO (it's a kind of chain reaction when higher organizational units (like the uberblock) are changed).


Usn's IT Blog for Linux, Oracle, Asterisk

Received on Thu Mar 06 2008 - 06:19:35 CST

Original text of this message