On Tue, Mar 30, 2021 at 4:58 PM Jim Albert <j...@netrition.com> wrote:
>
> How about a graceful restart right after a fresh full restart. Does that
> immediate graceful restart present the same issue or does the problem
> require some period of requests before a graceful restart will present the
> problem. Some process information ('top' on UNIX) might tell you if you
> have some httpd processes taking a long time to complete. You could watch
> your server-status over time to see what might be building up to the
> problem state.
>
I've tried this on my testbed, but it's difficult to replicate realistic
traffic with a mix of users, bots, probe attempts blocked by mod_security,
etc. However, during my tests I haven't noticed any considerable
long-running processes building up, so the full restart/graceful restart
scenario you mention doesn't appear to be any different than letting the
system run for a while. The problem seems to occur when 1) a graceful
restart is called, 2) the system is getting some connection attempts, and
3) the MPM settings aren't sufficient to handle the incoming requests while
waiting for old ones to close.
For now, I'm trying to solve the problem by increasing some MPM parameters,
but it's all a bit nebulous, since I'll never be completely sure that the
values are sufficient to prevent another deadlock situation in which the
server just hangs.
Thanks a lot for your tips.
>
