Sun Microsystems Netscape Enterprise Server, Administrator'S Manual

Page: 258 / 532

Common Performance Problems
258 Netscape Enterprise Server Administrator’s Guide
KeepAlive Connections Flushed
A web site that might be able to service 75 requests per second without
keepalives may be able be able to do 200-300 requests per second when
keepalives are enabled. Therefore, as a client requests various items from a
single page, it is important that keepalives are being used effectively. If the
KeepAliveCount
exceeds the
KeepAliveMaxCount
, subsequent
KeepAlive connections will be closed (or “flushed”) instead of being honored
and kept alive.
Checking
Check the
KeepAliveFlushes
and
KeepAliveHits
values. On a site
where KeepAlives are running well, the ratio of
KeepAliveFlushes
to
KeepAliveHits
is very low. If the ratio is high (greater than 1:1), your site is
probably not utilizing the HTTP KeepAlives as well as it could.
Tuning
To reduce KeepAlive flushes, increase the
MaxKeepAliveConnections
value in the magnus.conf file. The default value is 200. By raising the value,
you keep more waiting keepalive connections open.
Warning
On Unix systems, if you increase the
MaxKeepAliveConnections
value too
high, the server can run out of open file descriptors. Typically 1024 is the limit
for open files on Unix, so increasing this value above 500 is not recommended.
Log File Modes
Keeping the log files on verbose mode can have a significant affect of
performance.
Client-Host, Full-Request, Method, Protocol, Query-String, URI, Referer, User-
Agent, Authorization and Auth-User: Because the “obscure” variable cannot be
provided by the internal “accelerated” path, the accelerated path will not be
used at all. Therefore performance numbers will decrease significantly for
requests that would typically benefit from the accelerator, for example static
files and images.