litespeed + lsphp5 is optimized to reduce 500/503 errors.
for example, if one request is failed to serve by lsphp5 process, lsphp5's parent process may try start another lsphp5 process to serve the request, thus to reduce 500/503 error the end user can see. when one lsphp5 has handled many requests, the process itself may have problem e.g. occupying too many memory etc due to buggy php scripts. so in this case killing this process and start another new lsphp5 process to handle the new request, will reduce the chance of 500 errors.
you may still be able to see 500 error for example if your php script running for long time, but Server->Tuning->Connection Timeout (secs) is set to low. you can have a try to verify it.
Last edited by NiteWave; 03-07-2012 at 04:36 PM..