ADDING SECONDARY TIMESTAMP TO ASYNC PPRC
Original Publication Date: 2002-Oct-19
Included in the Prior Art Database: 2003-Jun-21
Problem Hosts that use Clean-Copy Async PPRC are granted that, at any time, the secondary storage is a consistent copy ofthe primary storage. However, due to the asynchronous nature of this function, the secondary storage is not necessarily a fully up-to-date copy of the primary storage. Solution A Secondary Timestamp provided by the subsystem. The Secondary Timestamp may help the host software in the realization of such a recovery strategy for Clean-Copy Async PPRC. To use this capability, the host must provide a synchronized timestamp in each of the host writes. This mechanism allows the host to query the secondary subsystem, getting a timestamp t , for which it is granted that any host writes with timestamp t were already propagated to the secondary.