[HOWTO] Fix MySQL after upgrade with different datadir

**mwjones** · October 15th, 2011

During the upgrade to 11.10, an option was presented to remove the custom /etc/mysql/my.cnf and replace it with the distro. The changes looked insignificant and I had a custom location in there for my datadir. After the upgrade, MySQL would not start.

All searches for the error log entry Can't start server : Bind on unix socket: Permission denied yielded results about setting permissions; but permissions had already been set correctly via chown at the time of install.

In the end, the solution was to merge the two apparmor files. New version of /etc/apparmor.d/usr.sbin.mysqld:

/{,var/}run/mysqld/mysqld.pid w,
/{,var/}run/mysqld/mysqld.sock w,
...
/RAMPAGE/mysql/ r,
/RAMPAGE/mysql/** rwk,

For search engine indexing, here is what other stuff looked like.

/var/log/mysql/error.log:

InnoDB: Starting shutdown...
InnoDB: Shutdown completed; log sequence number 0 7547009
[Note] /usr/sbin/mysqld: Shutdown complete

[Note] Plugin 'FEDERATED' is disabled.
InnoDB: Initializing buffer pool, size = 8.0M
InnoDB: Completed initialization of buffer pool
InnoDB: Started; log sequence number 0 7547009
[ERROR] Can't start server : Bind on unix socket: Permission denied
[ERROR] Do you already have another mysqld server running on socket: /var/run/mysqld/mysqld.sock ?
[ERROR] Aborting

/var/run/mysqld/:

Code:

$ sudo ls -Al /var/run/mysqld/ 
total 0

/etc/mysql/my.cnf:

[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock

[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0

[mysqld]
user = mysql
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
# datadir = /var/lib/mysql
datadir = /RAMPAGE/mysql
tmpdir = /tmp
skip-external-locking

bind-address = 127.0.0.1

**venkatesh20** · October 19th, 2011

Can you please give the commands that I can use to fix the issue. My mysql stopped working after upgrade to 11.10 due to the same issue mentioned here. Thanks