[Lazarus] Freepascal/Lazarus forum and Lazarus website outage wrap-up
marc at dommelstein.nl
Wed Feb 12 10:31:52 CET 2020
Now that everything seems to be normal, time for a wrap-up, what happened:
There were happening 2 things simultaneously
- an increased interest(?) from china
- one or two bots every second looking for SQL injections.
This caused a load on the original server configuration, apache using
mod_php, so it became unresponsive. Since the amount of traffic was
larger than normal, but still realistic, I decided to use fast-cgi to
remove the php overhead from the apache main process. With fast-cgi in
place I could now use the mpm_event module which can handle way more
connections to the server.
After some days of config tweaking everything should be fine..... not.
The server started to work OK until, according to netstat, about 800
sockets were in use, after which the server failed to respond. This
continued till the amount of sockets dropped to about 50 (due to
timeouts etc). Then the server was responsive again and the whole cycle
started over again.
After a lot of googling it appeared that this was caused by this issue
in apache https://bz.apache.org/bugzilla/show_bug.cgi?id=53555
A manual upgrade of apache to the latest version solved the problem.
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