HP XP7 Storage - Manual (Page 152)

a Synchronous state between the P-VOL and S-VOL. The Swap operation is required to copy
Non-transmitted pvol data within a given timeout value (specified by the -t <timeout> option).
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RAID300 microcode is 52-47-xx or over or RAID400 microcode is 10-00-xx or over
The S-VOL side RAID Manager will issue a Suspend for Swapping to the S-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 Resync for Swapping
operation will be performed (after the copy process). The Swap operation is required to copy
Non-transmitted pvol data within a given timeout value (specified by the -t <timeout> option).
SVOL-takeover function
RAID300 microcode is 52-47-xx and under or RAID400 microcode is 10-00-xx and under
This function makes it so the takeover node alone can use the secondary volume in SMPL state
(i.e., reading and writing are enabled), on the assumption that the remote node (possessing the
primary volume) cannot be used. The data consistency of the secondary volume is judged by its
status and fence level. If this check proves that data is not consistent, the SVOL-takeover function
fails.
RAID300 microcode is 52-47-xx or over or RAID400 microcode is 10-00-xx or over
The function makes it so the takeover node alone can use the secondary volume (except in COPY
state) in SSUS(PSUS) state (i.e., reading and writing are enabled), on the assumption that the
remote node (possessing the primary volume) cannot be used.
The data consistency of the secondary volume is judged by its status and fence level. If this check
proves that data is not consistent, the SVOL-takeover function fails. If this check proves that data
is consistent then this function will try to switch the svol to a primary volume using a Resync for
Swapping, and if it succeeds then this function will return Swap-takeover, else this function will
return SVOL-SSUS-takeover as the return value of horctakeover command. In case of a Host failure,
this function will be returned as Swap-takeover. In case of a ESCON or P-VOL site failure, this
function will be returned as SVOL-SSUS-takeover. A SVOL-takeover can be specified by the
granularity of a paired logical volume, CT group or volume group. If a SVOL-takeover is specified
for a volume group, a data consistency check is executed for all volumes in the group. Inconsistent
volumes are picked out and displayed in the execution log file as shown below:
Example
Group Pair vol Port targ# lun# LDEV#...Volstat Status Fence To be...
oradb1 ora001 CL1-A 1 5 145...S-VOL PAIR NEVER Analyzed
oradb1 ora002 CL1-A 1 6 146...S-VOL PSUS STATUS Suspected
Even so, the SVOL-takeover function enables the secondary volume to be used (i.e., reading and
writing are enabled) since it assumes that the remote node (possessing the primary volume) cannot
be used.
Continuous Access Asynchronous/Continuous Access Journal Specific behavior for svol-takeover
•
RAID300 microcode is 52-47-xx and under or RAID400 microcode is 10-00-xx and under
Before the S-VOL is changed to SMPL, the RAID300/400/450/500/600/700 will copy
non-transmitted pvol data (which remains in the FIFO queue of the primary volume) to the
S-VOL side. After the completion of a synchronous state between the P-VOL and S-VOL, the
S-VOL will be split and the state will be changed to SMPL.
In case of a ESCON or P-VOL site failure, this data synchronization operation may fail. Even
so, the SVOL-takeover function will do the force split to SMPL, and enable the secondary
152 Data replication operations with RAID Manager