啟動MySQL server 失敗，查看/var/log/mysqld.err

080329 16:01:29 [ERROR] Can't start server : Bind on unix socket: No such file or directory

080329 16:01:29 [ERROR] Do you already have another mysqld server running on socket: /var/run/mysqld/mysqld.sock ?

080329 16:01:29 [ERROR] Aborting

080329 16:01:29 InnoDB: Starting shutdown...

080329 16:01:30 InnoDB: Shutdown completed; log sequence number 0 4646872

080329 16:01:30 [Note] /usr/sbin/mysqld: Shutdown complete

百思不得其解，后來查看/var/db/pkg/dev-db/mysql-5.0.56/CONTENTS 文件，或者執(zhí)行equery f mysql（兩種方法非Gentoo linux 發(fā)布不適用），得知安裝文件中包含/var/run/mysqld，而這個目錄不存在，回憶起之前曾清空過/var/run目錄，一直以為這下面的內(nèi)容都是動態(tài)創(chuàng)建，刪除之后重啟系統(tǒng)即可，看來對mysql 來說還不是這么回事。

創(chuàng)建此目錄，并chown，問題解決。

# mkdir /var/run/mysqld

# chown mysql:mysql /var/run/mysqld