Cannot start MySQL: Another MySQL daemon already running with the same unix socket.

Today I had a little drama. I noticed that one of my servers was not working at all since the MySQL server was down. Initially I thought that maybe it was a problem of lack of free space in the hard drive. But it wasn’t. I am running CentOS in a 1and1 virtualserver.

This is the problem:

$ service mysqld restart
Stopping mysqld: [ OK ]
Another MySQL daemon already running with the same unix socket.
Starting mysqld: [FAILED]

So I started searching and found the solution:

$ mv /var/lib/mysql/mysql.sock /var/lib/mysql/mysql.sock.bak
$ service mysqld start
Starting mysqld: [OK]

This sorted it out nicely 🙂

Thanks to GeckoSEO for his solution in StackOverflow http://stackoverflow.com/questions/20407292/centos-another-mysql-daemon-already-running-with-the-same-unix-socket

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Apache logs in CentOS 6

If you need to know what is happening with your server, check-out the Apache logs here:

/etc/httpd/logs/

you will find somethint like this:

access_log

error_log

ssl_log

and so on

to see the logs in real time:

tail -f /etc/httpd/logs/access_log

this command f.e. will show you the access log that are currently happening in your site

 

mysql does not start and parallels is not working

I just experienced a major server breakdown in 1and1. MySQL crashed and when I tried to restart it the result would be negative:

 

Then I restarted the server and the problem persisted.

So my third action was to have a look at my Parallels Plesk web panel, and the result was that it would not load, showing a MySQL problem.

I then figured out that the problem could be a lack of memory, so I entered with ssh to the server and started listing directory sizes, using the great “du” linux command:

du -h –max-depth=1

until i found that the problem was in the backups folder:

/var/lib/psa/dumps

then I deleted one of the backup folders and could restart mysql

service mysqld restart

Thanks to this guide for the du parameters: http://www.linfo.org/du.html