IBM DS6000 - Manual (Page 382)

358 IBM System Storage DS6000 Series: Copy Services with IBM System z
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.
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 DD DDNAME=SYSIN
CESTPAIR DEVN (X'3C00') +
PRIM (X'3C00' 73081 X'00' X'0C') +
SEC (X'2C00' 27131 X'00' X'0C') +
ACTION(FAILBACK) +
MSGREQ(NO) CRIT(NO) +
OPTION(XD) CASCADE(NO)
CESTPAIR DEVN (X'3D00') +
PRIM (X'3D00' 73081 X'00' X'0D') +
SEC (X'2D00' 27131 X'00' X'0D') +
ACTION(FAILBACK) +
Global Copy
Primary
Primary
A
Primary
Primary
A
Primary
A
Host
Local site
2D01
2D00
2C00
Remote site
Primary
Primary
A
3D01
Primary
Primary
A
3D00
Secondary
B
3C00
Primary
Primary
A
3F01
Primary
Primary
A
3F00
Tertiary
C
3E00
FAILBACK
73081
27131
FCP links
FICON