HP XP Continuous Access Software User Manual
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HP StorageWorks Disk Array XP RAID Manager: User’s Guide
2. Host B detects the failure in host A and issues the takeover command
to make the S-VOL usable. If the S-VOL can continue processing,
host B takes over from host A and continues processing.
3. While host B is processing, the P-VOL and S-VOL can be swapped
using full copy (pairsplit –S, paircreate –vl) and the data updated by
host B is fed back to the new S-VOL, host A.
4. When host A recovers from the failure, host A takes over processing
from host B through the horctakeover swap-takeover command.
XP256 microcode 52-47-xx and over
XP512/48 microcode 10-00-xx and over
XP1024/128
XP10000
XP12000
P-VOL recovers.
pairresync
-swaps
Takeover
Takeover
Host A
Host B
P
vol
S
vol
Host A
Host B
S
vol
P
vol
c
d
unnecessary
Host A goes down.
Host A
Host B
P
vol
S
Vol
Host A
Host B
P
vol
Svol
SSUS
(SSWS)
Host A
Host B
S
vol
P
vol
c
d
e Only Difference data copied
P-VOL goes down.
Mirroring state
Takeover state
Recovery state
Failover
upon primary
host failure
Failover
upon primary
storage failure