Re: I've ran out of ideas
lukem.freebsd_at_cse.unsw.edu.au
Date: 11/19/04
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To: Aaron Glenn <aaron.glenn@gmail.com> Date: Fri, 19 Nov 2004 10:11:59 +1100 (EST)
On Thu, 18 Nov 2004, Aaron Glenn wrote:
> d# dd if=/dev/ad2s1 of=/dev/null bs=64k count=1000
> 1000+0 records in
> 1000+0 records out
> 65536000 bytes transferred in 1.353203 secs (48430278 bytes/sec)
> d#
>
> iostat has never gone above 3.8MB/s
The simple answer is that both iostat and dd are giving you the correct
results. Try your dd again with a smaller block size (like the 512 byte
default) and you should see that disk throughput is closer to what you are
seeing for your web server.
I would theorise that your web server is probably only issuing fairly
small disk reads, so your network performance is being bound by the disk.
To test this theory, you could:
* create an mfs partition and serve off it to see what kind of performance
you can get
* see if you can tweak the web server to use larger reads and writes.
In your original message you said that increasing the disk block size
improved performance, which would also indicate that you are being limited
by disk performance.
-- Luke _______________________________________________ freebsd-performance@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-performance To unsubscribe, send any mail to "freebsd-performance-unsubscribe@freebsd.org"
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