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Date: Mon, 24 Sep 2007 16:16:27 -0700
From: Andrew Sharp <andy.sharp@onstor.com>
To: "Maxim Kozlovsky" <maxim.kozlovsky@onstor.com>
Cc: "Fay Chong" <fay.chong@onstor.com>, "Paul Hammer"
 <paul.hammer@onstor.com>, "Jonathan Goldick" <jonathan.goldick@onstor.com>,
 "Jobi Ariyamannil" <jobi.ariyamannil@onstor.com>, "Brian Montero"
 <brian.montero@onstor.com>
Subject: Re: Wireshark Red Hat 3 and 5 NFS sequential performance
Message-ID: <20070924161627.066895ed@ripper.onstor.net>
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	<BB375AF679D4A34E9CA8DFA650E2B04E05B46316@onstor-exch02.onstor.net>
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The test that should demonstrate the problem is not two unidirectional
tests running at the same time, but a bidirectional test:


$ time dd if=chewbaca of=apeman bs=32k
9181+1 records in
9181+1 records out
300870117 bytes (301 MB) copied, 246.651 seconds, 1.2 MB/s

real    4m6.655s
user    0m0.000s
sys     0m0.940s


Cheers,

a

On Mon, 24 Sep 2007 14:40:01 -0700 "Maxim Kozlovsky"
<maxim.kozlovsky@onstor.com> wrote:

> What exactly was this test doing? Is it single direction, or
> bidirectional? The excel spreadsheet seems to imply that it is
> bidirectional.
> 
> I've tried bidirectional test and got completely different results
> with almost identical performance:
> 
> rhel3 - read 30MB/sec write 46MB/sec, 
> rhel5 - read 29.6MB/sec write 53.1MB/s
> 
> The test that I was running:
> 
> Rh3
> 
> time dd if=/1/file1 of=/dev/zero bs=32k ; skill -INT dd &
> 86187+0 records in
> 86187+0 records out
> 
> real    1m27.021s
> user    0m0.090s
> sys     0m11.740s
> 
> time dd if=/dev/zero of=/1/file2 bs=32k count=131072 ; skill -INT dd &
> 131072+0 records in
> 131072+0 records out
> 
> real    1m28.539s
> user    0m0.160s
> sys     0m19.460s
> 
> rh5:
> 
> time dd if=/dev/zero of=/1/file2 bs=32k count=131072 ; skill -INT dd&
> 131072+0 records in
> 131072+0 records out
> 4294967296 bytes (4.3 GB) copied, 80.8301 seconds, 53.1 MB/s
> 
> real    1m20.834s
> user    0m0.081s
> sys     0m14.097s
> 
> time dd if=/1/file1 of=/dev/zero bs=32k ; skill -INT dd &
> 72297+0 records in
> 72296+0 records out
> 2368995328 bytes (2.4 GB) copied, 80.0069 seconds, 29.6 MB/s
> 
> 
> real    1m20.023s
> user    0m0.047s
> sys     0m1.866s
> 
> Couple of things:
> 
> Do not post the results of running "vs stat agg" as actual
> performance, who knows what this code is doing. For the case of dd
> the performance can be measured directly as shown above.
> 
> With this high volume of traffic the Wireshark is lossy, you can not
> rely on it to tell anything about dropped packets. Look at the TCP
> stats for the number of retransmitted packets on the client and on
> the filer instead (which by the way was 0 in my test on both rhel5
> and rhel3).
> 
> In probably already doing this, but I thought I'll mention it just in
> case - you should unmount and remount the volume on the client and vol
> offline /vol online the volume on the filer between the tests to make
> sure consistent initial state is used.
> 
> Could you please create a script(s) which can be used to run your
> test(s) so we know we are on a same page?
> 
> Max
> 
> _____________________________________________
> From: Fay Chong 
> Sent: Sunday, September 23, 2007 5:49 PM
> To: Paul Hammer; Jonathan Goldick; Jobi Ariyamannil; Andy Sharp; Maxim
> Kozlovsky
> Cc: Brian Montero; Fay Chong
> Subject: Wireshark Red Hat 3 and 5 NFS sequential performance 
> 
> Hi,
> 
> Attached are some results from the Wireshark trace experiments on NFS
> sequential read and write with Red Hat Linux release 3 and 5. The
> Wireshark summaries seemed to have a lot of dropped packets as well as
> TCP acked lost segment and TCP Previous segment lost messages. The
> traces were saved so they can be reviewed by others. Also the vsvr
> stat agg throughput results are included. Tests were run with and
> without the wireshark. Let's talk about reviewing the data and
> refining the experiment.
> 
> Thanks
> 
> Fay
> 
>  << File: wiresharkexp1.xls >> 
> 
> 
> Fay Chong
> Sr. Performance Engineer
> ONStor, Inc.
> fay.chong@onstor.com
> 408.376.3130 (w)
> 
> 
