Hello Roch,
Friday, May 12, 2006, 5:31:10 PM, you wrote:
RBPE> Robert Milkowski writes:
>> Hello Roch,
>>
>> Friday, May 12, 2006, 2:28:59 PM, you wrote:
>>
>> RBPE> Hi Robert,
>>
>> RBPE> Could you try 35 concurrent dd each issuing 128K I/O ?
>> RBPE> That would be closer to how ZFS would behave.
>>
>> You mean to UFS?
>>
>> ok, I did try and I get about 8-9MB/s with about 1100 IO/s (w/s).
>>
>> But what does it proof?
RBPE> It does not prove my point at least. Actually I also tried
RBPE> it and it does not generate the I/O pattern that ZFS uses;
RBPE> I did not analyze this but UFS gets in the way.
RBPE> I don't have a raw device to play with at this instant but
RBPE> what we (I) have to do is find the right script that will
RBPE> cause 35 concurrent 128K I/O to be dumped into a spindle
RBPE> repeateadly. They can be as random as you like.
RBPE> This, I guarantee you, will saturate your spindle (or get
RBPE> really close to it). And this is the I/O pattern that ZFS
RBPE> generates during a pool sync operation.
ok, the same disk, the same host.
bash-3.00# cat dd32.sh
#!/bin/sh
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
dd if=/dev/zero of=/dev/rdsk/c5t500000E0119495A0d0s0 bs=128k &
bash-3.00# ./dd32.sh
bash-3.00# iostat -xnzC 1
extended device statistics
r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device
0.0 374.0 0.0 47874.6 0.0 33.0 0.0 88.1 0 100 c5
0.0 374.0 0.0 47875.2 0.0 33.0 0.0 88.1 0 100
c5t500000E0119495A0d0
extended device statistics
r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device
0.0 367.1 0.0 46985.6 0.0 33.0 0.0 89.8 0 100 c5
0.0 367.1 0.0 46985.7 0.0 33.0 0.0 89.8 0 100
c5t500000E0119495A0d0
extended device statistics
r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device
0.0 355.0 0.0 45440.3 0.0 33.0 0.0 92.9 0 100 c5
0.0 355.0 0.0 45439.9 0.0 33.0 0.0 92.9 0 100
c5t500000E0119495A0d0
extended device statistics
r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device
0.0 385.9 0.0 49395.4 0.0 33.0 0.0 85.4 0 100 c5
0.0 385.9 0.0 49395.3 0.0 33.0 0.0 85.4 0 100
c5t500000E0119495A0d0
extended device statistics
r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device
0.0 380.0 0.0 48635.9 0.0 33.0 0.0 86.7 0 100 c5
0.0 380.0 0.0 48635.4 0.0 33.0 0.0 86.7 0 100
c5t500000E0119495A0d0
extended device statistics
r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device
0.0 361.1 0.0 46224.7 0.0 33.0 0.0 91.3 0 100 c5
0.0 361.1 0.0 46225.3 0.0 33.0 0.0 91.3 0 100
c5t500000E0119495A0d0
These numbers are very similar to those I get with ZFS.
But it's much less than single dd writing with 8MB block size to UFS
or raw-device.
It still looks like issuing larger IOs does in fact offer much better
throughput.
--
Best regards,
Robert mailto:[EMAIL PROTECTED]
http://milek.blogspot.com
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
