Matt-Yes, I agree. It's a very frustrating scenario. My experience has been that the OS is just fine, with other services being unaffected by the Apache break down. It always happens at peak load periods, usually when several web applications are being hit hard at the same time. If something were logged, then perhaps we could clear the offending file, but something is clearly preventing Apache from reloading normally, and it appears to be Apache related.
I will look into the other suggestions offered thus far to see if I can find anything. Much appreciated, Rob Matthew Claridge wrote:
Rob,This won't be much help, but we've had this happen under severe load too (Apache 2.0.50, RHEL 3, 2.4.21-40). I haven't managed to find an explanation, but my current assumption is that either Apache or the OS is running out of some critical resource (file descriptors? socket limits? who knows.....)I would have expected Apache to log something if it failed to start due to something like that though, but it doesn't. It reports everything perfectly normally but is simply unable to serve any requests. None of the system logs show anything out of the ordinary either and other services continue to work fine. Indeed, we have a second Apache installation on the same box, used for a few test sites and under very little load, which continued to serve requests - this implies the server and OS were actually fine....Never saw anything like this while running v1.3 for 3 years, but the server was never under as much load as it is now so that may be why. It would just be useful if Apache would actually log something when it fails to start properly :-)Matt on 24/07/2006 18:46 Robert Fox said the following:Rob- Thanks for the response.This is definitely not a configuration issue. The error logs don't seem to indicate why only one process starts, but the children fail to start. I get a normal startup message in the logs. The only thing that clears this is re-booting the host.Are there other places where I could look? Rob Rob Wilkerson wrote:I'd check your config first. I forget the syntax for Redhat, but for my Knoppix system it's "/usr/sbin/apache2 -t". To check your system, locate the httpd executable and display it's help: "/path/to/httpd -h" Then, assuming everything checks out, check /var/log/httpd. Hopefully this will provide enough info to move forward. On 7/24/06, Robert Fox <rfox2@xxxxxx> wrote:Hello again-I haven't received any responses on this, so I thought maybe I could simplify my question. If Apache fails to restart, where should I look to find out why? The log files? System logs? Other Apache files (which ones)? Should I run adiagnostic while Apache is frozen? What should I look for?Thanks very much for any replies. I'm starting somewhat from ground zero here.Rob Fox -------- Original Message -------- Subject: Apache overwhelmed, restart fails Date: Tue, 18 Jul 2006 11:42:07 -0400 From: Robert Fox <rfox2@xxxxxx> To: users@xxxxxxxxxxxxxxxx Hello-We've been using Apache 2 here at Notre Dame libraries for several years now, and for the most part, the performance has been very reliable. However, there have been times during very peak usage periods when the Apache servers will freeze and essentially stop responding to further requests. We have several CGI applications running under the server that can be taxing, and sometimes Apache seems to get overwhelmed, and the maximum number of available server spawns are reached.When this happens, I've tried to restart Apache by first shutting it down and then starting the server again. However, what usually happens is that the first server process will start, and child processes do not spawn. This renders Apache useless again, and I'm usually forced to completely re-boot the server machine on which Apache is running in order to clear RAM and reset the network connections. Then, Apache comes up and everything is fine until the next incident. Hereare some specs on our installation: Server version: Apache/2.0.54 OS Version: Red Hat EL 3.0 (kernel 2.4.21-4.ELsmp) Modules loaded: PHP 5, authentication modules, etc. The CGI applications are mainly Perl based.I've looked in the Apache logs (both main and error) and there is no indication that the server is failing around the time that Apache freezes up. It seems odd that I can't stop the Apache servers and restart them, which solves 90% of these sorts of issues with Apache. Except for administrative purposes, I rarely need to restart Apache, so this isn't a major issue. But, I would like to know where to look to try and determine what is happening when I'm unable to restart Apache. It's odd that the first process would start but the child processes won't. Any ideas?Thank you for your help, Rob Fox ---------------------------------------------------------------------The official User-To-User support forum of the Apache HTTP Server Project.See <URL:http://httpd.apache.org/userslist.html> for more info. To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx " from the digest: users-digest-unsubscribe@xxxxxxxxxxxxxxxx For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx---------------------------------------------------------------------The official User-To-User support forum of the Apache HTTP Server Project.See <URL:http://httpd.apache.org/userslist.html> for more info. 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