Pivotal GemFire Versions 7.0.1.x,702.x,8.0.x, 8.1.x, 8.2.0.x, and 8.2.1.x
You might see the following warning or something similar in the logs:
2016-06-26 03:03:08,721 WARN DSClock.setServerCacheTimeOffset] New cache time offset calculated is off more than 151 ms from earlier offset.
The clock synchronization service is basically used to create timestamps that are used in active-active WAN conflict resolution. It basically keeps track of offsets among the member nodes clock and if the offset is more than 100ms it logs it, it does not initiate any background process.
These are harmless warnings. You can ignore it. If you are using any alert mechanisms which is bothering you, you have basically two options:
1.You can suppress these log warnings using log4j configurations. See the article,
2. Set gemfire property gemfire.disable-distributed-clock to true to disable the warnings.