Prepare To Return To The Local Site; Replicate The Changes From B To A - IBM System storage DS6000 Series Redbook

26.4.8 Prepare to return to the local site

At some time you will plan to return to the local site. The intention here is to apply the
changes from the B volumes to the A volumes before resuming operations at the local site.
Before you can apply these changes from the B to the A volumes, you have to establish paths
from B to A.

26.4.9 Replicate the changes from B to A

With the Global Copy paths between B and A defined, you may still be running the application
at the remote site, so updates keep arriving to the B volumes. Using the ACTION(FAILBACK)
parameter, we apply the changes from the B volumes to the A volumes; see Figure 26-5.
Local site
Primary
Primary
Primary
27131
Figure 26-5 Failback operation from B to A to prepare return to the local site
Example 26-22 illustrates how the failback is done using TSO commands. The failback
operation addresses the B volumes at the secondary site.
Example 26-22 Failback operation from B to A to prepare return to the local site
//* ---------------------------- TSO ----------------------------- ***
//* ESTABLISH Global Copy PAIR(S) FAILBACK B -> A ONCE A IS BACK ***
//* -------------------------------------------------------------- ***
//EPAIRFB EXEC PGM=IKJEFT01
//SYSPRINT DD SYSOUT=*
//SYSTSPRT DD SYSOUT=*
//SYSTSIN
CESTPAIR DEVN (X'3C00')
CESTPAIR DEVN (X'3D00')
358
IBM System Storage DS6000 Series: Copy Services with IBM System z
Host
2D01
A
2D00
A
2C00
Primary
Primary
A
FCP links
DD DDNAME=SYSIN
PRIM (X'3C00' 73081 X'00' X'0C')
SEC (X'2C00' 27131 X'00' X'0C')
ACTION(FAILBACK)
MSGREQ(NO) CRIT(NO) +
OPTION(XD)
PRIM (X'3D00' 73081 X'00' X'0D')
SEC (X'2D00' 27131 X'00' X'0D')
ACTION(FAILBACK)
FICON
Global Copy
FAILBACK
+
+
+
+
CASCADE(NO)
+
+
+
+
Remote site
3D01
A
3D00
A
3C00
Primary
3F01
Primary
Primary
B
Primary A
3F00
A
Secondary 3E00
Primary
Primary
Primary
C
Primary
Tertiary
73081