Re: [Jfs-discussion] jfs 'tunning' ?

[Christian K. <li...@ne...>]

On Tue, 30 Oct 2007, Peer-Joachim Koch wrote:
> EMC CX700
> riva:~ # time dd if=/dev/emcpowerb1 of=/dev/null bs=64k count=5000
> 5000+0 records in
> 5000+0 records out
>
> real    0m3.795s
> user    0m0.000s
> sys     0m0.420s

So, about 312MB in 3.7s or 84MB/s (if I didn't miscalculate this late at 
night :)

> OLD EMC FC4700
> riva:~ # time dd if=/dev/emcpowera1 of=/dev/null bs=64k count=5000
> 5000+0 records in
> 5000+0 records out
>
> real    0m9.531s
> user    0m0.010s
> sys     0m0.890s

still 32MB/s

> top - 21:12:21 up 15 days, 14:03,  1 user,  load avg: 1.23, 0.67, 0.57
> Tasks: 705 total,   1 running, 704 sleeping,   0 stopped,   0 zombie
> Cpu(s):   0.6% user,   4.6% system,   1.6% nice,  93.2% idle

hm, I'm often looking for a value named "wa" for "iowait" (also visible in 
vmstat(8)) - that way one could tell if the system is actually waiting for 
I/O to finish. you CPU is pretty much idle, I'd suspect the system to be 
more busy than that when waiting for/doing I/O.

> time   num of files  amount transfer  avg. rate       total time
> 17:47:01  2674994    768.18 MB     45048.29 KB/sec    03:00:12

So, you're getting 84MB/s from your EMC, 32MB from your "old" EMC (you 
don't use?), and your backup finishes with 44MB/s (instead of 84MB/s). But 
your box is not loaded or sluggish/unresponsive...strange

>>>   Do not write to the journal. The primary use of this option is to allow
>>>   for higher performance when restoring a volume from backup media. The
>>>   integrity of the volume is not guaranteed if the system abnormally
>>>   abends."
>>
>> You do not want to use this option on a mail server!

Oh, yeah...listen to what Dave says :)
I was only mentioning this option, not suggesting to actually use it for 
your particular setup.

>>>> While the backup is working Ican only see ~1MB/sec on the
>>>> SAN switch.

I'm a bit confused, because you mentioned 1MB/s in your last mail....?

C.
-- 
BOFH excuse #383:

Your processor has taken a ride to Heaven's Gate on the UFO behind Hale-Bopp's comet.