HP StorageWorks XP24000 Continuous Access Software User and Reference Guide, v01 (T5278-96002, June 2007)

• Suspend Range: Group or LU. Default = Group when one pair in each group is selected.
Default = Volume when two or m ore pairs in a group are selected.
Group: All pairs in the same consistency group(s) as the selected pair(s) will be split. You must
select
only one pair in each consistency group.
LU: O nly the specified pair(s) will be split, even if the error level of the pair is Group.
Note:
For the LU suspend range setting, if you select pairs with PAIR status and other than PAIR status
in the
same consistency g roup, an unexpected suspend m ay occur during the pa ir operations
(Pairsplit-r, Pairsplit-S, and Pairresync) under heavy I/O load conditions. You can estimate
whether or not the I/O load is heavy from the rate of sidefile cache (around 30%) or, if
youcannotsee thesidefile cacherate, from thefrequency of host I/O. Thesuspend pair
operations should b e performed under light I/O load conditions.
• Pending Update:Drain or Purge (default = Drain).
Drain: A s soon as the RCU accepts the Pairsplit-r 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 wi ll change the pa ir status from Suspending to PSUS.
Note: If there is no period of time without recordsets (that is, recordsets continue to be
generated) , the RCU will discontinue the original pairsplit-r operation and forcibly suspend the
pair.
Purge: The MCU will change the pair status from Suspending to PSUS as soon as the RCU
accepts the pairsplit-r operation. The MCU and RCU discard all pending recordsets and
mark the cylinders/tracks that contain discarded recordsets as modified in the P-VOL and
S-VOL bitmaps, respectively. When the pair is resynchronize d (pairresync), the P-VOL and
S-VOL bitmaps will be merged at the MCU, and all cylinders/tracks marked as modified will
be
copied to the S-VOL.
Note: If the MCU does not receive acknowledgement of the pairsplit-r operation from the RCU
within the copy pending time out setting, the MCU will forcibly suspend all affected Continuous
Access Asynchronous pairs.
Note: If youselect a pair from thevolumelistand change thesettings, andifyou useadrop-downlistto
set
blank to a parameter, the parameter takes the default value for each pair. If you select the settings
from the pre view list before applying the changed settings, and if you use a drop-down list to set blank to
a
parameter in the Pairsplit-r dialog box, the parameter value in the preview list will not be changed.
To split one or more Continuous Access pairs:
1. Connect to the MCU or RCU of the pair(s) to be split, op en the Continuous Access main window,
and
click the Pair Operation tab. You do not need to vary the P-VOL(s) offline.
Note: To use Enable for S-VOL Write option, you must connect to the MCU and select the
P-VOL of the pair(s).
2. In the tree, select the port, host group, desired CU, or the upper CU grouping.
3. In the list, select the Continuous Access pair(s) that you want to split. When a port is selected in
the
tree, the pair(s) can be selected from the current volume list.
Select either Continuous Acc ess Synchronous or Continuous Access Asynchronous pairs (not
both). The pair status must be PAIR. Use the Display Filter as needed to display the desired pairs
(for example, select PAIR status and Async only) (see “Display Filter” on page 103).
Note: If a LUSE pair that you want to split has the status PDUB, p er form the p airresync operation
on the
LUSE pair first to change the status to PAIR, and then you can split the pair. PDUB
indicates that the status of one or more individual LDEV pa irs within the LUSE pair is SMPL or
PSUE (due to some error condition).
4. Right-click, and click Pairsplit-r to open the Pairsplit-r dialog box (see Figure 50 on page 115).
5. On the Pairsplit-r dialog box, select the desired pairsplit options for the pair(s), and click Set to
close the Pairsplit-r dialog box. The preview list displays the requested pairsplit op eration(s).
6. Verify the requested operation(s) in the preview list. Make sure that the pairsplit op tions for
each pair are correct. The suspend kind option (S-VOL or P-VOL failure) and fence level pair
option (never, data, or status) determine whether the P-VOL will accept write I/O operations
after the pair is split.
To change one or more operations, select the operation(s) from the preview list, right-click,
and
click Modify. To remove one or more operations, select the operation(s) that you want to
delete from the preview list, right-click, and click Delete. To cancel all operations, select all the
operations in the preview list, right-click, and click the Delete command, or click the Cancel button.
116
Performing Continuous Access Pair Operations