Hi,
its me again thinking about measurement of response time. I have a new idea and just wanted to hear from you what you think about it. I am running a dd with a bs of 8k/4k against a fileserver for a couple of minutes and during different daytimes.
While the dd is running i do capture the networkstream and create a statistic for NFSv3-ops
tetherreal -i eth0 -z rpc,100003,3
This gives me an overview of the RTT's during this run of dd. What do you think about this method? I can use sio as well for generating random IO but the method will remain the same.
Best Regards and thanks in advance for any opinions on that
Jochen
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From: Miller, James [mailto:James.Miller@netapp.com] Sent: Friday, September 22, 2006 7:27 PM To: Willeke, Jochen Subject: Re: Response time measurement
Isn't it 8.72ms or .00872secs ... Jim Miller sent from blackberry
-----Original Message----- From: Willeke, Jochen Jochen.Willeke@wincor-nixdorf.com To: NetApp Toasters List toasters@mathworks.com Sent: Fri Sep 22 08:13:05 2006 Subject: Response time measurement
Hi folks,
i am still thinking about some figures which help me considering different fileservers. After doing some research i think one point is the response time given by the system.
I did a lot of testing with sio and but the results i got are some kind of strange.
A test with SIO e.g. brings following result:
./sio_ntap_linux 100 0 8k 100m 10 1 /mnt/test15 Version: 3.00
SIO_NTAP: Inputs Read %: 100 Random %: 0 Block Size: 8192 File Size: 104857600 Secs: 10 Threads: 1 File(s): /mnt/test15 Outputs IOPS: 114578 KB/s: 916626 IOs: 1145782 Terminating threads ...Killed
First there are the KB/S. Much to fast even for a 1Gbit network. And the second is the response time. I calculated the following:
1s / 114578 (IOPS) = 0,00872 ms (response time)
This cannot be true at all :-) Does SIO read the same block all the time (due to 0%random read), or do i have any kind of mistake in my test?!?
Perhaps someone can help.
Best Regards and a nice weekend
Jochen