发现一台从库的mysql同步停了，
用show slave status\g查看slave_io_running: no。启动slave也不成功，，也没看到错误号。后来查mysql的error日志有如下报错：
090216 21:06:10 [note] slave: received end packet from server, apparent master shutdown:
090216 21:06:10 [note] slave i/o thread: failed reading log event, reconnecting to retry, log 'mysql-bin.0444' position 77911
090216 21:06:11 [note] slave: connected to master 'rsync@10.10.10.10:3306',replication resumed in log 'mysql-bin.0444' at position 77911
用以前的办法弄半天也行，从网上一搜原来是因为server-id相同造成的，后来和另外一同事确认原来又配了一台从库，是直接复制的my.cnf配置文件造成的。改成不同的server-id后重启slave后同步恢复正常。