HP StorageWorks XP Remote Web Console Software - Manual (Page 26)

Table 6 XP Continuous Access Asynchronous pair status descriptions (continued)
S-VOL access P-VOL access Description Pair status
Pair Status for XP Continuous Access LUSE volumes only:
Read only Read/write XP Continuous Access pair consists
of LUSE volumes (for example,
OPEN3*n), and an individual LDEV
within this XP Continuous Access
LUSE pair failed due to some error
condition. The status of the XP
Continuous Access LUSE volume is
PAIR or COPY, and the status of one
or more LDEV pairs is PSUE or
SMPL. PDUB
Pair Status for XP Continuous Access Asynchronous only:
Read only Read/write Pair is not synchronized. This pair
is transitioning from PAIR or COPY
to PSUS/PSUE. When the
split/suspend pair operation is
requested, the status of all affected
pairs changes to Suspending. When
the split/suspend operation is
complete, the status changes to
PSUS/PSUE. Suspending
Read only Read/write Pair is not synchronized. This pair
is transitioning from PAIR, COPY, or
PSUS/PSUE to SMPL. When the
pairsplit-S operation is requested,
the status of all affected pairs
changes to Deleting. When the
pairsplit-S operation is complete, the
status changes to SMPL. Deleting
XP Continuous Access split types (PSUS)
Table 7 (page 27) describes XP Continuous Access split types. You can split an XP Continuous
Access pair at any time after the initial copy operation is complete. You must split an XP Continuous
Access pair to perform media maintenance on the P-VOL or change the S-VOL (S-VOL write enable).
When you split an XP Continuous Access Synchronous pair, the MCU ensures synchronization by
completing any pending update copy operation before changing the status to PSUS. After the pair
status changes to PSUS, the MCU stops performing update copy operations to the S-VOL and may
or may not continue accepting write I/Os for the P-VOL, depending on the P-VOL fence level and
pairsplit-r options. If the P-VOL accepts write operations while the pair is split, the MCU tracks
P-VOL cylinders updated. If you enabled the S-VOL write option when you split the pair, the RCU
tracks S-VOL cylinders updated while the pair is split. When the pair is resumed (pairresync), the
RCU sends the S-VOL cylinder bitmap to the MCU, and the MCU merges the P-VOL and S-VOL
bitmaps to determine which cylinders are out-of-sync.
When you split an XP Continuous Access Asynchronous pair, the MCU and RCU ensure
synchronization by completing or discarding pending update copy operations according to the
user-specified drain/purge pairsplit option. The MCU and RCU track recordsets discarded during
the pairsplit operation. After the pair status changes to PSUS, the MCU stops performing recordset
operations for the pair, continues accepting write I/Os for the split XP Continuous Access Async
P-VOL, and tracks P-VOL cylinders updated while the pair is split. If you enabled the S-VOL write
option when you split the pair, the RCU also tracks the S-VOL cylinders updated while the pair is
split. When the pair is resumed, the RCU sends the S-VOL cylinder bitmap to the MCU, and the
MCU merges the P-VOL and S-VOL bitmaps to determine which cylinders are out-of-sync.
26 Overview of XP Continuous Access operations