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Tuning recommendations for Apache HTTP Server w/ra_serf clients (MaxKeepAliveRequests)

From: Justin Erenkrantz <justin_at_erenkrantz.com>
Date: Sun, 23 Jan 2011 09:27:18 -0800

I think this probably belongs in the book, but I don't know exactly
where...so I'll ensure that it's noted again and let someone else
figure out where it should live.

As we start to have more users with ra_serf, we should also recommend
that httpd server admins bump up their MaxKeepAliveRequests from 100
(default) to at least 1000. This'll help ra_serf utilize TCP
connections more efficiently - as ra_serf issues 2 HTTP requests per
file that it needs to check out or update.

ra_serf has heuristics so that it'll work gracefully under the default
settings (and determine what the value actually is), but you'll get
better network performance if you can utilize fewer TCP connections.
This way, ra_serf will only need to open a new connection every 500
files rather than every 50. (Honestly, there is really no reason that
it couldn't be 10000.)

If we also have a tuning section, we should remind folks to also
enable mod_deflate (SetOutputFilter DEFLATE in their Location block)
as that'll help a bit when transferring XML content back and forth.
mod_deflate will come at a slight latency penalty, but that'll be
offset for folks with slower connections taking less time to transfer
the responses overall.

FWIW, I've already asked ASF infra to bump up the MaxKeepAliveRequests
settings for svn.apache.org.

Thanks! -- justin
Received on 2011-01-23 18:27:59 CET

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