Relay_Log_File gets reset when reboot/shutdown the server

[Prachid Tiyapanjanit]

Greeting,

I've got a weird problem here. Currently I have 2 MySQL servers running Master-Master (Active-Passive).
Everything seems working fine except when I reboot or shutdown one of the server.
When it is back up the relay log file getting reset and the slave on the server will fail to start.
This problem won't happen when I manually restart MySQL service via '/etc/init.d/mysqld restart or stop && start'.

my.cnf reads:
[mysqld]
user=mysql
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
log-error=/var/log/mysql/mysqld.log
log-slow-queries=/var/log/mysql/slow-query.log

server-id=10

log-bin=mysql-bin
log-slave-updates
sync_binlog=1

max_allowed_packet=5M
max_connections=200
thread_concurrency = 4

[mysqld_safe]
log-error=/var/log/mysql/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

Thanks

PT.