mysqlがホストでダウンしているというNagiosからのダウンタイムアラートを受け取りました。ホストにログインしたところ、mysqlerror.logファイルに次のエラーが見つかりました。これをトラブルシューティングするための適切な手順は何ですか?
root@ubuntu:/var/log# tail -f mysql/error.log
101202 11:09:21 [ERROR] Can't open the mysql.plugin table. Please run
mysql_upgrade to create it.
101202 11:09:21 InnoDB: Started; log sequence number 0 44233
101202 11:09:21 [ERROR] /usr/sbin/mysqld: Can't find file: './mysql/host.frm'
(errno: 13)
101202 11:09:21 [ERROR] Fatal error: Can't open and lock privilege tables:
Can't find file: './mysql/host.frm' (errno: 13)
101202 11:09:51 [Note] Plugin 'FEDERATED' is disabled.
/usr/sbin/mysqld: Can't find file: './mysql/plugin.frm'
(errno: 13)
101202 11:09:51 [ERROR] Can't open the mysql.plugin table. Please run
mysql_upgrade to create it.
101202 11:09:52 InnoDB: Started; log sequence number 0 44233
101202 11:09:52 [ERROR] /usr/sbin/mysqld: Can't find file: './mysql/host.frm'
(errno: 13)
101202 11:09:52 [ERROR] Fatal error: Can't open and lock privilege tables:
Can't find file: './mysql/host.frm' (errno: 13)
101202 11:10:22 [Note] Plugin 'FEDERATED' is disabled.
/usr/sbin/mysqld: Can't find file: './mysql/plugin.frm'
(errno: 13)
101202 11:10:22 [ERROR] Can't open the mysql.plugin table. Please run
mysql_upgrade to create it.
101202 11:10:22 InnoDB: Started; log sequence number 0 44233
101202 11:10:22 [ERROR] /usr/sbin/mysqld: Can't find file: './mysql/host.frm'
(errno: 13)
101202 11:10:22 [ERROR] Fatal error: Can't open and lock privilege tables:
Can't find file: './mysql/host.frm' (errno: 13)