Estaba trabajando en un servidor y de pronto dejo de funcionar el mysql cuando intentaba arrancarlo simplemente obtenia:

# /etc/init.d/mysqld start
MySQL Daemon failed to start.
Starting mysqld: [FAILED]

Entonces me puse a revisar los logs y obtuve el siguiente reporte:

[root@server ~]# tail -f /var/log/mysqld.log
121227 09:25:22 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
121227 9:25:22 [Warning] The syntax ‘–log-slow-queries’ is deprecated and will be removed in a future release. Please use ‘–slow-query-log’/’–slow-query-log-file’ instead.
121227 9:25:22 [Note] Plugin ‘FEDERATED’ is disabled.
121227 9:25:22 [Note] Plugin ‘InnoDB’ is disabled.
121227 9:25:22 [ERROR] Unknown/unsupported storage engine: InnoDB
121227 9:25:22 [ERROR] Aborting

121227 9:25:22 [Note] /usr/libexec/mysqld: Shutdown complete

121227 09:25:22 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended

Bueno pues al parecer no reconoce el motor InnoDB entonces me puse a revisar la configuracion de mysql en my.cnf y encontre la siguiente linea.

[root@server ~]# vi /etc/my.cnf
1 [mysqld]
2 datadir=/var/lib/mysql
3 socket=/var/lib/mysql/mysql.sock
4 # Default to using old password format for compatibility with mysql 3.x
5 # clients (those using the mysqlclient10 compatibility package).
6 old_passwords=1
7 init_connect=’SET NAMES utf8′
8 log-slow-queries = slowq.log
9 long_query_time = 15
10 #log-queries-not-using-indexes
11 query-cache-type = 1
12 query-cache-size = 1500M
13 query_cache_limit=64M
14 wait_timeout=10
15 connect_timeout=10
16 skip-innodb
17 skip-external-locking
18 thread_concurrency=1
19 thread_cache_size=64
20 max_user_connections= 100
21 max_connections = 100
22 low-priority-updates=1
23 max_allowed_packet = 64M
24 table_cache = 16384
25 max_heap_table_size = 128M
26 tmp_table_size = 128M
27 join_buffer_size = 16M
28 open_files_limit=65535
29 key_buffer_size=512M
30 symbolic-links=0
31
32 [mysql.server]
33 user=mysql
34 basedir=/var/lib
35
36 [mysqld_safe]
37 log-error=/var/log/mysqld.log
38 pid-file=/var/run/mysqld/mysqld.pid
39 max_connections = 150

Si se fijan en la linea 16 esta la variable skip-innobd que al parecer el mysql no logra ejecutar, entonces la solucion mas sencilla fue comentar dicha liena:

1 [mysqld]
2 datadir=/var/lib/mysql
3 socket=/var/lib/mysql/mysql.sock
4 # Default to using old password format for compatibility with mysql 3.x
5 # clients (those using the mysqlclient10 compatibility package).
6 old_passwords=1
7 init_connect=’SET NAMES utf8′
8 log-slow-queries = slowq.log
9 long_query_time = 15
10 #log-queries-not-using-indexes
11 query-cache-type = 1
12 query-cache-size = 1500M
13 query_cache_limit=64M
14 wait_timeout=10
15 connect_timeout=10
16 #skip-innodb
17 skip-external-locking
18 thread_concurrency=1

Luego inicia mysql

[root@server ~]# /etc/init.d/mysqld start
Starting mysqld: [ OK ]

Luego puedes volver a descomentar la liena.

Insisto este es una solucion temporal y dependara de tu sistema ya que existen otras soluciones dependiendo el sistema y la configuracion de tu mysql.

MFCP!!