First of all, hello to everyone as it's my first post here. Until now, all of my questions have been already asked and answered :) not this time unfortunately.
I have a VPS (Ubuntu 14.04 32bit, 2 GB mem) which is my "sandbox". I test my PHP/MySQL application and learn to use and manage Linux server. Since about a week MYSQL performed quite slow. It took a few seconds for a SELECT (no JOINs) in a ~2 million records table.
Today, I found some time to take care of it and to look for a problem. I've read a few discussions on MySQL optimisation. I found out via SolusVM control panel that server uses 100% memory. I tried top to check what process consumes most of memory but it didn't sum up to 100%. The largest process was MySQL with about 33% of memory.
I rebooted the server and after first reboot it closes all connections in ~2 minutes. After each reboot in ~2 minutes I get:
- an error in Putty "Server unexpectedly closed netword connection".
- any domain hosted on that server returns "connection timeout error"
- WinSCP tries to connect to server and returns no error, starts over and over again to make a connection
In syslog file I have no info about problems - just an info that mysql tables need an update.
In these 2 minutes between log in (via Putty) and closing connection by server I tried to stop some services, like mysql, cron, postfix, apache and proftpd. After each test one by one server was closing connection in ~2 minutes after reboot - so it had no impact on server behaviour.
What I've noticed watching Memory Usage in SolusVM control panel. When the connections are closed, the memory usage drops from ~40% to ~20% and than in a few seconds increases to ~50% and later in a few minutes it reaches 100%.
What else can I check to find out what happens in these 2 minutes after reboot?
I need to also add that since my last login to the server in the root directory appeared "aquota.group" and "aquota.user" files. I don't understand why yet. But tried quotaoff command. After this, server closed connections in ~2 minutes after reboot - so...nothing changed.