Software User Manual

Pair Status
XP Continuous Access displays the pair status for each volume in the connected storage system.
Table 9 (page 31) lists and describes the XP Continuous Access pair status descriptions. The MCU
maintains the status of the P-VOL and can change the pair status of the P-VOL and S-VOL. The RCU
maintains the status of the S-VOL and can change the pair status of the S-VOL but not the P-VOL.
The MCU detects when the RCU changes the S-VOL status (if the path status is normal) and changes
the P-VOL status accordingly. You can display the detailed pair status information at the Remote
Web Console (XP Continuous Access Detailed Information dialog box) or at the host (RAID Manager
Pairdisplay command).
A volume that is not assigned to an XP Continuous Access pair has the status SMPL. When an XP
Continuous Access pair is started, the MCU changes the status of the P-VOL and S-VOL to COPY.
When the initial copy operation is complete, the MCU changes the status of both volumes to PAIR.
When an XP Continuous Access pair is split by the user (pairsplit-r), the MCU/RCU changes the
status of the P-VOL and S-VOL to PSUS (if the path status is normal). When a pair is suspended
due to an error condition, the MCU/RCU changes the P-VOL and S-VOL status to PSUE (if the path
status is normal). When a pair is released by the user from the MCU (pairsplit-S), the MCU changes
the status of the P-VOL and S-VOL to SMPL (if path status is normal). When a pair is released from
the RCU, the RCU changes the S-VOL status to SMPL, and the MCU detects the pair release (if path
status is normal) and changes the P-VOL status to PSUS.
When an XP Continuous Access pair is split or suspended, the MCU generates a service information
message (SIM) to notify the host(s). If SNMP is installed and operational for the storage system,
this SIM results in an SNMP trap, which indicates the reason for suspension.
XP Continuous Access LUSE Pair Status
For XP Continuous Access LUSE pairs only, the PDUB status indicates that the status of the XP
Continuous Access LUSE pair is COPY or PAIR, but the status of one or more individual LDEV pairs
within the XP Continuous Access LUSE pair is SMPL or PSUE (due to an error condition).
XP Continuous Access Asynchronous Pair Status
The XP Continuous Access Suspending and Deleting transitional states occur when a request to
change an XP Continuous Access Asynchronous pair status has been accepted, but the change to
the requested status (PSUS, PSUE, or SMPL) is not yet complete. These states are not reported to
the host. In the case of Suspending, both the user and the MCU can request the status change. In
the case of Deleting, only the user can request the status change. If the user requested the status
change, the final status is reported at the end of the transition. If an error caused the status to
change to PSUE, the suspended status is reported at the beginning of the transition.
Table 9 XP Continuous Access Pair Status
S-VOL AccessP-VOL AccessDescriptionPair Status
Read/writeRead/writeThis volume is not currently assigned to an XP
Continuous Access pair. When this volume is added
SMPL
(simplex)
to an XP Continuous Access pair, its status will change
to COPY.
Read onlyRead/writeThe initial copy operation for this pair is in progress.
This pair is not yet synchronized. When the initial copy
is complete, the status changes to PAIR.
COPY
Read onlyRead/writeThis pair is synchronized. Updates to the P-VOL are
duplicated on the S-VOL.
PAIR
Read only;Read/writeThis pair is not synchronized, because the user has split
this pair (pairsplit-r) or because the user has released
PSUS
(pair
suspended-split)
Read and write, if
the write enable
this pair from the RCU (pairsplit-S). For XP Continuous
Access Asynchronous pairs, the MCU and RCU keep
(see
Table 10 (page
split option is
selected.
track of any recordsets that were discarded during the
pairsplit-r operation. While a pair is split, the MCU
33) on page
Pair Status 31