If you observe that this latency is too high for a consistent period of time, this indicates that there is a concern about storage performance and you must check the logs on the storage array for any indication of a failure. If failures are logged on the storage array side, corrective action should be taken. Contact your storage vendor for information regarding checking logs on the array.
Also check if these messages are generated when there were any scheduled tasks, such as backups, replications, etc., as these can also cause intermittent performance hits.
If the message is generated because of an overload condition, attempt to reduce the load on the affected storage device. If the storage device is overloaded, reduce the load on the storage device.
If running a LUN replication tool, pause the task from the storage end and attempt a storage vMotion to a different datastore. This should help improve the I/O operations.
For more/related information on diagnosing overload/performance issues, see Using esxtop to identify storage performance issues (1008205).