Blue and many others,
Thanks for the response. You are right, I need to provide a few more
details.
The files are 10 MBs each, the Apache version is 1.2.12 (should I
upgrade? were there scalability enhancements since then?), the Linux
kernel version is 2.2.19pre16 (unfortunately, I cannot go above 2.2.x for
the purposes of this test).
The following limits were increased in the Linux kernel: NR_TASKS (max
processes) to 4000, FD_SETSIZE (max open files) to 4096, various TCP
parameters in /proc/sys/net/ipv4, etc. Am I forgetting something? Is
there a good online guide to tweaking your Linux to handle higher loads
that I am perhaps not aware of?
Actually, the problem that I am having is not so much with Apache waiting.
It's with the resets.
Another thing that I was not aware of is the need to bump up MAX_PROCESSES
in http_main.c manually. I always sort of assumed changing
process-related parameters in the httpd.conf would do the trick. So I
will try increasing that now... Are there any other limits
defined in the source-code that may need to be increased?
Thank you very much.
Stan Rost
On Thu, 22 Mar 2001, Blue Lang wrote:
> On Wed, 21 Mar 2001, Stanislav Rost wrote:
>
> > A little about the setup: two P2-400's stressing another P2-400 with
> > >400-500 concurrent ongoing downloads of large files at any given
> > instant of time (so high concurrency levels are implicit). Apache is
> > directed to create at least that many threads on startup.
>
> how large are the files? what version of apache are you using? why are you
> using http to transfer large files? it's stinky at it.
>
> if it's a 1MB file, you're out of bandwidth in .002 seconds (on a 100Mb
> link) and apache will queue up the rest of your downloads and wait, wait,
> wait.
>
> > My other question is for anyone who has ever successfully benchmarked
> > Apache under Linux and produced nice-looking graphs: what system and
> > web server parameters did you tweak to obtain high-stress results?
> > What was your setup?
>
> i've been able to maintain load avgs of around 230 on a late 2.3 kernel on
> a celeron 433, pushing about 1300 reqs/second over a 100Mb switch. i was
> using ab and a smallish (~3k) index.html. the only things i did were turn
> off logging and set max clients to 255. i was experimenting with serving
> files from RAM disks and loopback mounted file systems at the time, it was
> nothing scientific.
>
> anyways, that's 1,000,000 small requests every 10 minutes or so. this was
> probably with apache 1.3.12 or so.
>
> on a really nice switch with a dual proc sun Netra, i was able to get
> really close to 11MB/sec from an apache install tuned pretty much the same
> way with very, very low load on the web server.
>
> --
> Blue Lang http://www.gator.net/~blue
> 2315 McMullan Circle, Raleigh, North Carolina, USA 919 835 1540
>
>
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Stanislav "Stan" Rost /
A.K.A. The Progressor /
/
http://cs-people.bu.edu/prgrssor /
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