Jeroen Roodhart wrote:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: RIPEMD160
Hi Freddie, list,
Option 4 is to re-do your pool, using fewer disks per raidz2 vdev,
giving more vdevs to the pool, and thus increasing the IOps for the
whole pool.
14 disks in a single raidz2 vdev is going to give horrible IO,
regardless of how fast the individual disks are.
Redoing it with 6-disk raidz2 vdevs, or even 8-drive raidz2 vdevs
will give you much better throughput.
We are aware of the configuration being possibly suboptimal. However,
before we had the SSDs, we did test earlier with 6x7 Z2 and even 2way
mirrorset setups. These gave better IOPS but not significantly enough
improvement (I would expect roughly a bit more than double the
performance in 14x3 vs 6x7) . In the end it is indeed a choice
between performance, space and security. Our hope is that the SSD
slogs "serialise" the data flow enough to make this work. But you
have a fair point and we will also look into the combination of SSDs
and pool-configurations.
Also, possibly the Vortex Turbo SSDs aren't as good latency wise as I
expected. Maybe the Sun SSDs will do a lot better. We will find this
out when they arrive (due somewhere in february).
With kind regards,
Jeroen
-
I haven't seen this mentioned before, but the OCZ Vertex Turbo is still
an MLC-based SSD, and is /substantially/ inferior to an Intel X25-E in
terms of random write performance, which is what a ZIL device does
almost exclusively in the case of NFS traffic.
In fact, I think that the Vertex's sustained random write IOPs
performance is actually inferior to a 15k SAS drive.
--
Erik Trimble
Java System Support
Mailstop: usca22-123
Phone: x17195
Santa Clara, CA
Timezone: US/Pacific (GMT-0800)
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
