Date: Thu, 18 Nov 2004 17:53:04 -0800 From: Aaron Glenn <aaron.glenn@gmail.com> To: "lukem.freebsd@cse.unsw.edu.au" <lukem.freebsd@cse.unsw.edu.au> Cc: freebsd-performance@freebsd.org Subject: Re: I've ran out of ideas Message-ID: <18f6019404111817533b93cbba@mail.gmail.com> In-Reply-To: <Pine.LNX.4.61.0411191006310.5596@wagner.orchestra.cse.unsw.EDU.AU> References: <20041118101026.55888.qmail@web14121.mail.yahoo.com> <20041118105543.10295.qmail@web41208.mail.yahoo.com> <18f6019404111809224fb97c06@mail.gmail.com> <Pine.LNX.4.61.0411191006310.5596@wagner.orchestra.cse.unsw.EDU.AU>
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On Fri, 19 Nov 2004 10:11:59 +1100 (EST), lukem.freebsd@cse.unsw.edu.au <lukem.freebsd@cse.unsw.edu.au> wrote: > 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. The /www partition it's reading from was made with -b 65536 and -f 8192. > 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. That was my first hunch; hence creating a separate partition with obscene blocksizes (-: > 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. I doubt increasing it even more would help. Law of diminishing returns and all that; then again I'm no expert. Thoughts? Regards, aaron.glenn
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