On 20/07/2010 11:46, Roy Sigurd Karlsbakk wrote:
----- Original Message -----
Hi,
for zfs raidz1, I know for random io, iops of a raidz1 vdev eqaul to
one physical disk iops, since raidz1 is like raid5 , so is raid5 has
same performance like raidz1? ie. random iops equal to one physical
disk's ipos.
Mostly, yes. Traditionl RAID-5 is likely to be faster than ZFS because of ZFS
doing checksumming, having the ZIL etc, but then, trad raid5 won't have the
safety offered by ZFS
That depends on wither or not you are CPU bound, if you aren't CPU bound
then the checksuming may not mater. Depending on what RAID5 hardware
you are using (and how much available NVRAM it has) the ZFS RAIDZ could
be faster.
See Jeff Bonwick's blog posting describing RAID-Z
http://blogs.sun.com/bonwick/entry/raid_z
And Adam Leventhal's blog posting describing RAID-Z3
http://blogs.sun.com/ahl/entry/triple_parity_raid_z
The current code base supports raidz1, raidz2, raidz3 (triple parity)
--
Darren J Moffat
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