On 11/06/2010 09:22, sensille wrote:
Andrey Kuzmin wrote:
On Fri, Jun 11, 2010 at 1:54 AM, Richard Elling
<richard.ell...@gmail.com<mailto:richard.ell...@gmail.com>> wrote:
On Jun 10, 2010, at 1:24 PM, Arne Jansen wrote:
> Andrey Kuzmin wrote:
>> Well, I'm more accustomed to "sequential vs. random", but YMMW.
>> As to 67000 512 byte writes (this sounds suspiciously close to
32Mb fitting into cache), did you have write-back enabled?
>
> It's a sustained number, so it shouldn't matter.
That is only 34 MB/sec. The disk can do better for sequential writes.
Note: in ZFS, such writes will be coalesced into 128KB chunks.
So this is just 256 IOPS in the controller, not 64K.
No, it's 67k ops, it was a completely ZFS-free test setup. iostat also confirmed
the numbers.
It's a really simple test everyone can do it.
# dd if=/dev/zero of=/dev/rdsk/cXtYdZs0 bs=512
I did a test on my workstation a moment ago and got about 21k IOPS from
my sata drive (iostat).
The trick here of course is that this is sequentail write with no other
workload going on and a drive should be able to nicely coalesce these
IOs and do a sequential writes with large blocks.
--
Robert Milkowski
http://milek.blogspot.com
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