Apache 1.1.1 & MaxClients LOCK OUT problem

Apache 1.1.1 & MaxClients LOCK OUT problem

Post by David Thomps » Tue, 24 Sep 1996 04:00:00

We are experiencing the LOCK OUT problem.  Once we reach MaxClients, all
web activity grinds nearly to a halt.  Being a rather large university
that is beginning to use the web in a BIG way not only to supplement
classroom instruction, but in a fairly large trial, the ONLY means of
instruction this is an unacceptable level of performance.

I have been increasing MaxClients slowly but keep hitting the LOCK OUT
problem.  It would seem that I need to have the number of processes/user
to further increase MaxClients to a number of clients well in excess of
what we will ever achieve (with some margin for cgi processes).  I note
that as I increase MaxClients, my load level increases proportionally,
though so far without apparently being detrimental to regular telnet or
netnews sessions.

What do others in a similar environment do?

(BTW, we running HPUX 10.10 on two tightly coupled K210's with ServiceGuard.)

Timeout 20
MinSpareServers 5
MaxSpareServers 10
StartServers 5

# Limit on total number of servers running, i.e., limit on the number
# of clients who can simultaneously connect --- if this limit is ever
# reached, clients will be LOCKED OUT, so it should NOT BE SET TOO LOW.
# It is intended mainly as a brake to keep a runaway server from taking
# Unix with it as it spirals down...

MaxClients 160

David Thompson, Systems Programmer
Computer Center, CSU Northridge
18111 Nordhoff St.
Northridge, CA  91330-8280
(818) 885-2787


1. Apache MaxClients problem

We have a web server with the following configuration:

Sun Solaris 5.7
Apache SSL version 1.3.26
     MaxClients=256, MaxREquestsPerChild 10000
Mod SSL version 2.8.10
OpenSSL version 0.9.6g
JRun version 3.1.15506 (using Apache as external web server)

The web site averages around 125,000 hits per day.  On an average day
the number of Apache Clients/threads at any given time ranges between

Occasionally, the number of Apache Clients will inexplicably max out
at 256 or stay at an abnormally high number.  The clients don't ever
seem to free up and the only thing we can do to resolve the problem is
restart both Apache and JRun, causing a brief outage.  Obviously, this
does not sit well with our client.  It causes serious response time
issues with users and/or completely prevents them from getting to the

Unfortunately, we have been unable to find a root cause.  It does not
appear to be caused by an increase in activity on the site, a DOS
attack, or a user slamming the site.  Nothing unusual is showing up in
any of the logs.

Any insight or help in resolving this problem would be greatly


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