Hello. I have been struggling for a few months to solve a problem with
an Apache web server. First i'll try to describe the symptoms, then
give details about the configuration and what i have tried so far. I
would greatly appreciate any suggestions on how to diagnose and correct
the problem.
Symptom 1:
After starting Apache during periods of high load the server appears to
run fine for awhile ("awhile" is highly variable but on the order of 90
minutes) then starts returning empty pages. When the empty pages start,
Apache's error_log gets filled with lines like this:
[Thu Sep 07 09:09:11 2006] [notice] child pid 3579 exit signal
Segmentation fault (11), possible coredump in /etc/httpd/core
These errors are very intermittent during periods of light load. I have
had CoreDumpDirectory defined for awhile and have amassed quite a
collection of core files. This is the first few lines of what gdb
reports for one of them:
(gdb) bt
#0 0x0000002a99ff2492 in preg_replace_impl (ht=Variable "ht" is not
available.)
at /usr/src/redhat/BUILD/php-4.3.9/ext/pcre/php_pcre.c:1154
#1 0x0000002a9a0ac255 in execute (op_array=0x552afe2798)
at /usr/src/redhat/BUILD/php-4.3.9/Zend/zend_execute.c:1640
#2 0x0000002a9a0a9386 in execute (op_array=0x552aff7fb8)
at /usr/src/redhat/BUILD/php-4.3.9/Zend/zend_execute.c:1684
#3 0x0000002a9a0a9386 in execute (op_array=0x552b0e26c8)
at /usr/src/redhat/BUILD/php-4.3.9/Zend/zend_execute.c:1684
#4 0x0000002a9a0a9386 in execute (op_array=0x552af80db8)
at /usr/src/redhat/BUILD/php-4.3.9/Zend/zend_execute.c:1684
Symptom 2:
A further symptom of problems is found in PostgreSQL's logs. The web
applications the server runs rely on PostgreSQL, which logs several
times per minute messages like this:
Sep 7 10:16:09 sun12 postgres[7411]: [1-1] LOG: unexpected EOF on
client connection
PostgreSQL is configured to accept 256 connections, twice as many
children as Apache should spawn.
Configuration:
The server is a Sun v40z, which is a dual Opteron box with 2 GB RAM. It
is running Red Hat Linux Enterprise AS 4.4 64-bit, with Apache 2.0.52,
PHP 4.3.9, and eAccelerator 0.9.4. The server's purpose is to run Horde
and Imp, with the latest versions of those packages and a few other
Horde components (Ingo, Passwd, and Turba).
Apache is installed with Red Hat's RPMs. PHP is compiled from Red Hat's
source RPMs; i added mcrypt support which is not included by default
(but needed to improve performance of Horde).
Below is a list of things i have tried that did not work. After each
test that failed to provide results i reverted to the previous
configuration.
1) Using Red Hat's RPMs even though they don't have mcrypt support. This
did nothing.
2) Upgrading PHP to the latest 4.4.x (x==2 at the time i tried that),
compiled from source. This had no effect.
3) Removed eAccelerator. Problems remained, but server responds to
requests a bit slower (as would be expected).
4) Running with a uniprocessor kernel. No effect on the errors.
5) Switched Apache and PHP to 32-bit. The rest of the system is 64-bit.
This also had no effect.
Over the last few months i have exchanged many messages on the Horde,
Imp, and Apache users mailing lists trying to track down the problems.
The consensus seems to be that i need to ask on the PHP forums. Does
anyone recognize this problem? Do you know a solution for the problem?
------------------------------------------------------------------------
Dan Ramaley Dial Center 118, Drake University
Network Programmer/Analyst 2407 Carpenter Ave
+1 515 271-4540 Des Moines IA 50311 USA
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