MySQL Dying After a Few Days I just recently upgraded to Ubuntu 15.04 from 14.04, I guess the MySQL was also upgraded to 5.6. Is there a reason why my database stops working. Rebooting the system is the only fix for it, but it still dies again in a day or two. It's been going on for a few weeks since I updated to 15.04. I also removed and reinstalled MySQL.

2015-09-22 22:16:28 14273 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future$  
2015-09-22 22:16:28 14273 [Note] Plugin 'FEDERATED' is disabled.  
2015-09-22 22:16:28 14273 [ERROR] Function 'innodb' already exists  
2015-09-22 22:16:28 14273 [Warning] Couldn't load plugin named 'innodb' with soname 'ha_innodb.so'.  
2015-09-22 22:16:28 14273 [ERROR] Function 'federated' already exists  
2015-09-22 22:16:28 14273 [Warning] Couldn't load plugin named 'federated' with soname 'ha_federated.so'.  
2015-09-22 22:16:28 14273 [ERROR] Function 'blackhole' already exists  
2015-09-22 22:16:28 14273 [Warning] Couldn't load plugin named 'blackhole' with soname 'ha_blackhole.so'.  
2015-09-22 22:16:28 14273 [ERROR] Function 'archive' already exists  
2015-09-22 22:16:28 14273 [Warning] Couldn't load plugin named 'archive' with soname 'ha_archive.so'.  
2015-09-22 22:16:28 14273 [Note] InnoDB: Using atomics to ref count buffer pool pages  
2015-09-22 22:16:28 14273 [Note] InnoDB: The InnoDB memory heap is disabled  
2015-09-22 22:16:28 14273 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins  
2015-09-22 22:16:28 14273 [Note] InnoDB: Memory barrier is not used  
2015-09-22 22:16:28 14273 [Note] InnoDB: Compressed tables use zlib 1.2.8  
2015-09-22 22:16:28 14273 [Note] InnoDB: Using Linux native AIO  
2015-09-22 22:16:28 14273 [Note] InnoDB: Using CPU crc32 instructions  
2015-09-22 22:16:28 14273 [Note] InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137363456 bytes) failed; errno 12  
2015-09-22 22:16:28 14273 [ERROR] InnoDB: Cannot allocate memory for the buffer pool  
2015-09-22 22:16:28 14273 [ERROR] Plugin 'InnoDB' init function returned error.  
2015-09-22 22:16:28 14273 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.  
2015-09-22 22:16:28 14273 [ERROR] Unknown/unsupported storage engine: InnoDB  
2015-09-22 22:16:28 14273 [ERROR] Aborting
[Note] InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137363456 bytes) failed; errno 12


errno 12 is Out of memory - So probably you did not set any value for the innodb_buffer_pool_size and the default is used. Depending on your previous version the default might change on upgrade. Or you did have it configured but the upgrade rewrote your config? Or your new Ubuntu just needs more memory for itself.

Change the value, add more RAM, find some memory hog which might eat your RAM or enable swap (might slow everything down when it hits the swap).