503 errors with FireFox only

[nolnet]

Hi all,

Seems my 503 issue is occuring on vbulletin forums with medium to high traffic.

This is the original thread: http://www.litespeedtech.com/support/forum/showthread.php?t=3801

However, it now is occuring on another server with a busy vbulletin forum and the logs show it only happens to Firefox users as well. I've had 3 different server companies review the issue and paid Litespeed support as well to no avail. I agree with Litespeed it is likely not a LSWS issue but rather some obsure PHP issue. I'm just hoping someone might have some more suggestions.

I quick google search shows other vbulletin forum owners running litespeed with the same issue. Most of them report the errors only show when hitting the file showthread.php. What could be so different about that file and Firefox to throw a 503 error is the $64,000 question.

Thanks in advance.

 

[mistwang]

We noticed similar behavior from another web site.
I think it relates to the cookie sent by browser, PHP somehow does not like it and do something strange.

The difficult part is that we cannot reproduce it easily to trouble shoot it further.

 

[NiteWave]

not sure if the issue has any relation to:
https://wiki.mozilla.org/Firefox3_Timeout_Problem

if a known user frequently encountered 503 error, can he try
network.http.keep-alive = false
described in above link, and see if any difference?

 

[admonet]

Not to resurrect a dead thread but we too are having this issue.

The issue appears to be with the bulk of our Firefox users. This issue cannot be traced as PHP does not core dump when this issue occurs. Litespeed just complains that it cannot communicate with PHP and fails with 503.

We've also noted this exact issue with FCGI (instead of using LSAPI) and we still experience 503 errors even with a "vanilla" custom-compiled PHP CGI.

We've also reverted from PHP 5.3.2 to 5.2.x with no difference in behavior.

All of our sites run vBulletin and I am wondering if there is some type of invalid cookie vBulletin could be sending that litespeed does not like to handle? Is there any way to capture this issue in logs because there is NO CORE dump.

When switching to Apache all runs fine. Our timeouts are very high (900s on most options) and the script is not timing out, the issue just seems to follow one particular user (or user IP in the logs)

Rebooting and clearing their cache seems to work but I am confused. What is litespeed doing differently that Apache is not? Is it adding some invalid data to a cookie? Is it possibly ballooning the size of the cookie past the max set in litespeed?

Litespeed, you have to help us, this is happening on multiple large installations of vBulletin that we host but there is nothing we can do to resolve it at this time. We have even upgraded to litespeed 4.0.16 (not even released yet)

Please help and please tell us what could be happening.

 

[mistwang]

The easiest way is to let PHP dump core files.
set LSAPI_ALLOW_CORE_DUMP
http://www.litespeedtech.com/php-litespeed-sapi.html

for lsphp5 external app, then run "ulimit -a" from PHP script, make sure core limit is high enough. Make sure the directory holding the script has the correct permission.

For Apache, it wont produce 503 error, instead, it will give a blank page or something when PHP engine crashes.

 

[admonet]

The easiest way is to let PHP dump core files.
set LSAPI_ALLOW_CORE_DUMP

for lsphp5 external app, then run "ulimit -a" from PHP script, make sure core limit is high enough. Make sure the directory holding the script has the correct permission.

For Apache, it wont produce 503 error, instead, it will give a blank page or something when PHP engine crashes.

We're working with support on this issue. Keep in mind that we have followed your troubleshooting guide for PHP and cannot locate a core file in the working directory for the script returning intermittent (what appears session/cookie related) 503 errors.

This issue persists across more than five installations of vbulletin with Litespeed. We've custom compiled and removed any and all modules loaded in PHP with the same results.

We'll work with support to troubleshoot the issue. With no core dump from PHP, and no helpful information from debug logging, it's very difficult to cut these errors out. Please consider creating more verbose logging in your application so we can track down specific communication errors with PHP (e.g. returning the raw data litespeed is receiving from the lsapi app)

Thanks,
Adam

 

[MentaL]

Dont mean to bump an old thread but I just had this problem then upon reading the above comment in which it may relate to the output cookie I decided to clear my firefox cookies for the entire offending domain and the result was success...

503 stopped.