Here is what I see in SSH:
Stopping mysqld ...
Shutting down MySQL... [ OK ]
Upgrading MySQL 5.1 to 5.5
Preparing... ########################################### [100%]
1:MySQL-shared ########################################### [ 25%]
2:MySQL-server ########################################### [ 50%]
3:MySQL-devel ########################################### [ 75%]
4:MySQL-client ########################################### [100%]
Starting MySQL.The server quit without updating PID file (/var/lib/mysql/redacted.pid). [FAILED]
Giving mysqld a few seconds to start up...
Looking for 'mysql' as: /usr/bin/mysql
Looking for 'mysqlcheck' as: /usr/bin/mysqlcheck
FATAL ERROR: Upgrade failed
/usr/bin/mysqlcheck: Got error: 2002: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2) when trying to connect
cp: `/usr/lib/libmysqlclient.so' and `/usr/lib/mysql/libmysqlclient.so' are the same file
Restarting MySQL.
Here is the error log:
140819 12:00:01 mysqld_safe mysqld from pid file /var/lib/mysql/redacted.pid ended
140819 12:00:16 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
140819 12:00:16 [Note] Plugin 'FEDERATED' is disabled.
140819 12:00:16 InnoDB: The InnoDB memory heap is disabled
140819 12:00:16 InnoDB: Mutexes and rw_locks use GCC atomic builtins
140819 12:00:16 InnoDB: Compressed tables use zlib 1.2.3
140819 12:00:16 InnoDB: Using Linux native AIO
140819 12:00:16 InnoDB: Initializing buffer pool, size = 128.0M
140819 12:00:16 InnoDB: Completed initialization of buffer pool
InnoDB: Error: log file ./ib_logfile0 is of different size 0 50331648 bytes
InnoDB: than specified in the .cnf file 0 5242880 bytes!
140819 12:00:16 [ERROR] Plugin 'InnoDB' init function returned error.
140819 12:00:16 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
140819 12:00:16 [ERROR] Unknown/unsupported storage engine: InnoDB
140819 12:00:16 [ERROR] Aborting
140819 12:00:16 [Note] /usr/sbin/mysqld: Shutdown complete
140819 12:00:16 mysqld_safe mysqld from pid file /var/lib/mysql/redacted.pid ended
Hope this helps!
Thanks,
-Joe