Hitachi MP-96RD625-01 manual Primary host can add time stamps Secondary site Primary site

(2) Primary host (can add time stamps)

	(2)		Secondary site
	Primary site
(1)			External
	(3)		port
	Primary data		(5)
		(4)	Secondary data
	volume		volume
	Master JNL VOL		Restore JNL VOL
	Primary storage system 1	Secondary storage system 1
			Target
(1)	(3)		port
			(5)
	Primary data	(4)	Secondary data
	volume		volume
	Master JNL VOL		Restore JNL VOL
	Primary storage system 2	Secondary storage system 2

Figure 3-6 A URz Operation When Two Primary Storage Systems and

Two Secondary Storage Systems are Used

The numbers in Figure 3-6 indicate the order that the processing is performed, and correspond to the numbers in the numbered procedure below:

1.The primary host issues write requests to primary storage systems. Time stamps are added to the data to be written.

2.The primary storage systems receive the write requests, and then notify the primary host that primary data volumes are updated.

3.The URz journal obtain function stores data updated in primary data volumes to master journal volumes as journal data. Time stamp information added by the primary host will be added to journal data. Also, sequence numbers indicating the order of writing will be added to journal data.

4.The URz journal copy function copies journal data from the master journal volumes to the corresponding restore journal volumes. This journal copy operation will be performed asynchronously with the journal obtain operation.

Chapter 3 Preparing for Universal Replicator z/OS Operations 3-19

Hitachi Universal Replicator for IBM /OS User’s Guide