Apama requires the system clock to move forwards without large jumps, and never move backwards. This applies only to the underlying clock measuring UTC (Coordinated Universal Time) seconds since 1970; daylight saving time and time zone adjustments will not affect Apama's timers.

Discontinuities in the system clock can result in disconnections and/or unpredictable application behavior, especially with any application-level timeouts. Virtual machine infrastructure can be particularly vulnerable to such clock issues. Consult your virtual machine vendor's documentation or support for recommendations on how to correctly handle time for the host operating system you are using and ensuring that the virtual machine host's clock is correctly synchronized.

Outside of virtual machines, we would strongly recommend using the Network Time Protocol (NTP) on both Windows and Linux, and ensuring that system administrators never make manual adjustments to the system clock. NTP's default configuration is to handle time adjustments by slightly slowing down or speeding up time, avoiding any sudden jumps. The Windows Time service can cause large time jumps and is not suitable.