HP StorageWorks XP Remote Web Console Software - Manual (Page 158)

need to maintain synchronization of the TrueCopy for Mainframe pair. This setting is
functionally equivalent to CSUSPEND without the optional PRIMARY parameter.
•
Asynchronous Parameters:
Suspend Range: Group or Volume (default = Group when one pair is selected, default =
Volume when two or more pairs are selected). The CSUSPEND TSO command supports
the TrueCopy for Mainframe Asynchronous suspend range option.
Group: The MCU/RCU will suspend all other pairs in the same consistency group as the
selected pair. This option is available only when one pair is selected.
◦
Volume: The MCU/RCU will suspend only the specified pair(s), even if the error level of
the pair is group.
For the Volume suspend range setting, if you select pairs with duplex status and other
than duplex status in the same consistency group, unexpected suspend may occur during
the pair operations (suspend, resynchronize, release) under heavy I/O load conditions.
You can estimate whether the I/O load is heavy or not from the rate of sidefile cache
(around 30%), or if you cannot see the sidefile cache rate, from the frequency of host
I/O. The suspend pair operations should be performed under light I/O load conditions.
◦ Pending Update: Drain or Purge (default = Drain). The CSUSPEND TSO command supports
the TrueCopy for Mainframe Asynchronous pending update suspend option.
Drain: As soon as the RCU accepts the Suspend Pair operation, the RCU will finish settling
all pending recordsets for the pair. After settling all pending recordsets, if there are no
recordsets for a fixed period of time, the MCU will change the pair status from Suspending
to Suspended.
If there is no period of time without recordsets (that is, recordsets continue to be generated),
the RCU will discontinue the original Suspend Pair operation and forcibly suspend the
pair.
Purge: The MCU will change the pair status from Suspending to Suspend as soon as the
RCU accepts the suspend pair operation. The MCU and RCU discard all pending
recordsets and mark the cylinders/tracks that contain discarded recordsets as modified
in the M-VOL and R-VOL bitmaps, respectively. When the pair is resynchronized, the
M-VOL and R-VOL bitmaps will be merged at the MCU, and all cylinders/tracks marked
as modified will be copied to the R-VOL.
If the MCU does not receive acknowledgement of the suspend operation from the RCU
within the copy pending timeout setting, the MCU will forcibly suspend all affected
TrueCopy for Mainframe Async pairs and report an IEA491E host console message.
CAUTION: The QUIESCE option of the CSUSPEND command has been disabled by APAR
OW15247 or APAR OW15248. See either of these APARs and the latest IBM PPRC documentation
for detailed information on the QUIESCE option of the CSUSPEND command. Please check with
your HP account team before using the CSUSPEND command with the QUIESCE option to suspend
TrueCopy for Mainframe pairs on XP storage systems. If the CSUSPEND command with the QUIESCE
option is issued to certain volumes (for example, active SPOOL, PAGE, or CATALOG datasets,
active SYSRES volume), the attached host(s) may enter a deadlock condition and may require a
storage control IML to correct the condition. TrueCopy for Mainframe Asynchronous does not
support the CSUSPEND/QUIESCE option.
If you select a pair from the volume list and change the settings, and if you use a drop-down list
to set blank to a parameter, the parameter takes the default value for each pair. If you select the
settings from the preview list before applying the changed settings, and if you use a drop-down
list to set blank to a parameter in the Suspend Pair dialog box, the parameter value in the preview
list will not be changed.
To suspend one or more TrueCopy for Mainframe pairs:
158 Performing TrueCopy for Mainframe Pair Operations