I have two instances of zabbix running on two different RHEL servers. Data presented in web user interface on one are off by 2 hours and on the other by 3 hours (ahead). For example instead of 15:00 it says 17:00. Timezone in /etc/php.ini is set properly to America/Vancouver (the same as settings on my desktop). I use MySQL and database settings are ok as well. calling 'select now() from dual' test returns correct time.
returns correct time and I also created link
ln -sf /usr/share/zoneinfo/America/Vancouver /etc/localtime
and restarted zabbix server and the agent. Time in graphs is still two hours ahead.