Use MySQL UNIX_TIMESTAMP or time() Consistently
On multi server environment, where timestamp might differs, cause of misconfigured timezone or some other stuff, then the output of UNIX_TIMESTAMP() on master server will differ with slave server time() or UNIX_TIMESTAMP().
As of this moment, I notice the problem had caused slave server unable to report its current status/log, due to premature deletion of the new log on monitor_data. From all the other monitoring functions, they all using UNIX_TIMESTAMP() to store the data, while during the deletion, it uses time() - 4 * 60. The temporary fix that I applied: Change file: /user/local/ispconfig/server/mods-available/monitor_core_module.inc.php Find function: _delOldRecords Modified: $old Into: UNIX_TIMESTAMP() - 240
I believe for future update, it will be best to have time adjustment between server being stored on server table, so every update from slave server to master server using php time() function will be added/subtracted from this difference. The time difference will be adjusted every once in a while for the sake of consistency between 2 different server.