HP StorageWorks XP Remote Web Console Software - Manual (Page 117)

TrueCopy for z/OS user guide 117
NOTE: The CESTPAIR TSO command does not support the initial copy priority option. When
CESTPAIR is used to establish TC390 pairs, the initial copy operations are performed in the order
that the CESTPAIR commands are issued.
• Difference Management: Select Auto, Cylinder, or Track as the basis for managing the differential
data. The default is Auto. When you select Auto, either Cylinder or Track is selected depending on
the basic size of the logical volume image.
• The CFW Data option specifies whether the CFW data will be copied to the R-VOL:
If Copy to R-VOL is selected, the MCU will copy the CFW data to the R-VOL.
If Only M-VOL is selected, the MCU will not copy the CFW data to the R-VOL. This setting is
recommended for two reasons: (1) copying the CFW data impacts disk array performance and (2)
CFW data is typically used for temporary files (for example, sort work datasets) that are not usually
required for disaster recovery.
NOTE: If a TC390 pair is established using PPRC commands, the CFW data option is set to the
Copy to R-VOL setting.
NOTE: By using Remote Copy Function Switch, you can set the following option with CESTPAIR:
CFW data = only M-VOL. If you want to use this function, please contact your HP account support
representative.
• The DFW to R-VOL option (TC390 Synchronous only) specifies whether the MCU will suspend a
TC390 volume pair when the RCU cannot execute DFW to the R-VOL:
If DFW not required is selected, the MCU will not suspend the TC390 volume pair when DFW on
the RCU is blocked. This option is recommended if you need to maintain synchronization of the
TC390 volume pair.
NOTE: If a TC390 pair is established using PPRC commands, the DFW to R-VOL option is set to
not required.
If DFW required is selected, the MCU will suspend the pair when DFW on the RCU is blocked. This
option is recommended if you need to maintain high MCU I/O performance.
CAUTION: The interaction of the DFW required setting and the M-VOL fence level setting can
cause a host application to fail with a permanent I/O error when attempting to update an M-VOL.
Keep track of which volume pairs have the DFW required setting and verify that DFW to the R-VOL
is not blocked.
NOTE: The DFW to R-VOL setting does not affect the I/O performance of the M-VOLs. If one side
of cache is closed due to an RCU failure, the TC390 copy operation still uses DFW. The only
difference between not required and required is that new pairs cannot be established with the
DFW-to-R-VOL required option when one side of RCU cache is closed (the add pair operation
fails).
• Asynchronous Parameters: Can be selected only for the Asynchronous pair(s).
• CT Group: C/T Group. This option specifies the consistency group for the pair(s) being added
(TC390A only). All TC390A pairs must be assigned to a consistency group.