HP XP Cluster Extension Software Administrator Guide

4 XP Cluster Extension recovery procedures
XP disk pair states
“Disk pair states” (page 45) provides basic disk pair state information. The disk pair state transition
process is complex; see the Continuous Access and Continuous Access Journal documentation for
more information.
Table 3 Disk pair states
DescriptionState
The primary (master) disk of a disk pairP-VOL
The secondary (slave) disk of a disk pairS-VOL
A disk with no pair affinity to any other diskSMPL
(This could be shown in pairdisplay outputs for your Continuous Access Software disk if you
accidentally exported the Business Copy environment variable HORCC_MRCF. In such a case,
the MU number field will not be empty.)
The disk is either a primary disk or a secondary disk. If both (P-VOL and S-VOL) disks are in PAIR
state, Continuous Access Software updates the secondary disk based on the primary disk.
PAIR
If you see only one disk in PAIR state (while the second disk is in another state), one of the following
has occurred:
• The pair affinity on only one site of the disk pair was deleted.
• A takeover command has been invoked on the secondary site, while no data has been written
to the primary site and the Continuous Access link was down.
• A takeover command has been invoked on the primary site with the fence level configured to
DATA to release the fenced disk, while the Continuous Access link was down. (The secondary
disk would stay in PAIR state.)
The pair affinity has been manually suspended or a takeover operation has been invoked on the
secondary site with the fence level configured to NEVER. (In this case, the secondary disk would
have the state SSUS-SSWS.)
PSUS
The pair affinity has been manually suspended or a takeover operation has been invoked on the
secondary site. In this case, the secondary disk would have the state SSWS if you invoke
SSUS
pairdisplay with the –fc option. In fence level ASYNC, the disk could also show PFUL or
PFUS when using the –fc option.
Only the secondary disk could show SSUS. With the –fc option of pairdisplay, you can
check whether somebody manually suspended the pair or a takeover command had been invoked.
SSUS -
SSWS
A prior takeover command is indicated by the SSWS state. In this case, the secondary disk is
mandatory and a resynchronization can be done only from the S-VOL site.
The disk is in a failure mode. Either the Continuous Access link is down, or the disk must be
replaced.
PSUE
The disk is in a failure mode. Either the Continuous Access link is down, or the disk must be
replaced. This is a special state of PSUE. If you have configured several disks into a LUSE
PDUB
configuration, where several LDEVS are combined to create an extended size disk and one or
more disks are in an error condition, this state will be shown.
This state is used to indicate that a threshold of the side file area in the disk array cache has been
reached. This state can be seen with fence level ASYNC only. See the Continuous Access
documentation for more information.
PFUL
This state is used to indicate that the side file is full and the disk array was not able to transfer
the cache content to the remote disk array for a certain time. The disk pair has been suspended
PFUS
to continue processing host I/O. This state can be seen with fence level ASYNC only. See the
Continuous Access documentation for more information.
XP disk pair states 45