Apache not releasing memory
Posted: Tue Dec 05, 2017 10:50 pm
Whilst sound asleep, a WordPress installation of mine hosted on Vesta 0.9.8-17 with Apache2 + nginx had it's xmlrpc.php file totally hammered by some bot somewhere for a few hours.
There's thousands of requests like the one below - almost 4 a second.
NixStats had Apache's memory usage at ~93%. Server has 2GB of RAM.
When I blocked the IP, the requests immediately stopped and so did the bot's connection attempts.
Apache's memory usage however did not come down.
I monitored it for 30 mins and am certain that the offending IP or any other IP did was not attempting to connect, but memory usage still did not come down.
I had to restart Apache for it to free up all the RAM it was using.
If there are no requests, why didn't apache's memory usage come down on it's own?
There's thousands of requests like the one below - almost 4 a second.
Code: Select all
69.197.x.x - - [05/Dec/2017:05:12:53 +0000] "POST /xmlrpc.php HTTP/1.0" 200 926 "-" "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)"
When I blocked the IP, the requests immediately stopped and so did the bot's connection attempts.
Apache's memory usage however did not come down.
I monitored it for 30 mins and am certain that the offending IP or any other IP did was not attempting to connect, but memory usage still did not come down.
I had to restart Apache for it to free up all the RAM it was using.
If there are no requests, why didn't apache's memory usage come down on it's own?