HP XP7 Storage - Manual (Page 151)

Unconformable: A pair of volumes are not conformable to each other as a pair (i.e. one pvol, one
svol). The takeover command execution terminates abnormally.
Reject: The takeover command is rejected, and the operation terminates abnormally.
Unknown: The attribute of the remote node is unknown and cannot be identified. This means that
the remote node system has gone down or cannot communicate over the LAN.
SSWS: Since the SSWS state is referring to a Suspend for Swapping with SVOL Side only, the
SSWS state is displayed as SSUS (SVOL_PSUS) by all commands except the -fc option of the
pairdisplay command.
Swap-takeover function
The P-VOL status at the remote node is PAIR or PFUL (Continuous Access Synchronous async and
over HWM) and the S-VOL has mirroring consistency. In such a state, it is possible to swap the
primary and secondary volume designations to continue operation. The takeover command internally
executes the operating commands (explained later) step by step, to swap the primary and secondary
volume designations. Swapping can be specified at the granularity of volume pair, CT group or
volume group.
RAID300 microcode is 52-47-xx and under or RAID400 microcode is 10-00-xx and under
1. As the preliminary step of swap-takeover, the command orders a Simplex (SMPL) state,
indicating the end of pairing for the remote volume (P-VOL).
If this step fails, the swap-takeover function is disabled and a SVOL-takeover is executed.
2. The local volumes of the takeover node are paired in the No Copy mode, and switched to
the primary volume.
If this step fails, step 1 is re-executed to cancel the operation of step 2, then an SVOL-takeover
is executed. If step 1 fails again, the swap-takeover command fails.
RAID300 microcode is 52-47-xx or over or RAID400 microcode is 10-00-xx or over
The swap-takeover function does not use Simplex and No Copy mode for Swapping anymore in
order to guarantee mirror consistence more surely, and it is included as a function of SVOL-takeover.
1.
As the preliminary step of swap-takeover, the command orders a Suspend for Swapping
(SSWS) for the local volume (S-VOL).
If this step fails, the swap-takeover function is disabled and it will be returned at an error.
2. The command orders a Resync for Swapping for switch to the primary volume that the local
volume (S-VOL) is swapped as the NEW_PVOL and re-synchronizes the NEW_SVOL based
on the NEW_PVOL. As for the number of simultaneous copy tracks, if the remote host is known
then the command will use the value of PVOL specified at paircreate time, else(remote host is
Unknown) the command will use a default of 3 as the number of tracks for Resync for Swapping.
If this step fails, the swap-takeover function will be returned at SVOL-SSUS-takeover, and the
local volume(S-VOL) is maintained in SSUS(PSUS) state which permits WRITE and maintaining
delta data(BITMAP) for the secondary volume. Also this special state is displayed as SSWS
state using -fc option of pairdisplay command.
Continuous Access Asynchronous/Continuous Access Journal Specific behavior for swap-takeover
•
RAID300 microcode is 52-47-xx and under or RAID400 microcode is 10-00-xx and under
The P-VOL side RAID Manager will issue a Pairsplit command to the P-VOL side
RAID300/400/450/500/600/700. Non-transmitted data which remains in the FIFO queue
(sidefile) of the primary volume will be copied to the S-VOL side and a swap operation will
be performed (after the copy process). The Swap-command will return after the completion of
Continuous Access Synchronous operations 151