Replication - always broken when poweroff one of the nodes

[TOMASZ SERWANSKI]

Hello,

GotMySQL on 2 DB servers, seems to work fine - until someting will happen :) In general:
- Replication works perfectly
- When any of servers is rebooted (linux; 'reboot') still both nodes are consistent after restart/reboot
- Unfortunately, when simulating power outage (servers are VMs on Citrix Xen; do it by pressing'force shutdown' from Xen console), passive server becomes active and works fine, but after restarting 'failed' node (previously active, now passive), 'failed' one does not start to replicate from 'new' master' (hope described it clearly); errors are like '..[ERROR] Slave SQL: Error 'Duplicate entry..'

My configs look like below:

[mysqld]
log-bin
server_id=1 #obviously there is '2' on other node
sync_binlog=1
innodb_flush_log_at_trx_commit=1
relay_log_info_repository=table
master_info_repository=table
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
symbolic-links=0
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

And, to be honest, I have no idea where to look for solution (today tried with 'sync_binlog' and 'innodb_flush_..' - none helped).

Could hopefully anyone advice what may be problem/reason?

regards
Tomasz