Hitachi TAGMASTORE MK-90RD011-25 User Manual page 244

4.10.1.4 PVOL-Takeover Function
The PVOL-takeover function releases the pair state as a group, since that maintains the
consistency of the secondary volume at having accepted horctakeover command when the
primary volume is fenced ("data or status" & "PSUE or PDUB" state, "PSUE or PDUB" volume
are contained in the group). This function allows the takeover node to use the primary
volume (i.e., reading and writing are enabled), on the assumption that the remote node
(possessing the secondary volume) cannot be used. PVOL-takeover can be specified for a
paired volume or a group.
The PVOL-takeover function executes the following two commands:
PVOL-PSUE-takeover: Changes the primary volume to the suspend (PSUE, PSUS) state
which enables write I/Os to all primary volumes of the group. The action of the PVOL-
PSUE-Takeover causes PSUE and/or PSUS to be intermingled in the group. This
intermingled pair status is PSUE as the group status, therefore pairvolchk command
returned give priority PSUE(PDUB) than PSUS as the group status. This special state turns
back to the original state when the pairresync command is issued.
PVOL-SMPL-takeover: Changes the primary volume to the simplex (SMPL) state. First,
PVOL-takeover executes PVOL-PSUE-takeover further than PVOL-SMPL-takeover. If the
PVOL-PSUE-takeover function fails, the PVOL-SMPL-takeover function is executed.
Note for Hitachi TrueCopy Async/UR: PVOL-Takeover will not be executed. It will be Nop-
Takeover, since the fence level for TrueCopy Asynchronous is Async, which is the same as
Never.
226 Chapter 4 Performing CCI Operations