Regression and recovery of ca, Regression and recovery of ca 356, Scenario – HP XP Continuous Access Software User Manual
Page 356: The p-vol detects a failure in the s
356
HP StorageWorks Disk Array XP RAID Manager: User’s Guide
Regression and recovery of CA
The figure below shows a diagram of regression and recovery where
horctakeover
is not needed.
Scenario
1. The P-VOL detects a failure in the S
-
VOL or the link and suspends
mirroring. (It depends on the fence level whether host A continues
processing or host B takes over processing from host A.)
2. The P-VOL changes its paired volume status to PSUE and keeps track
of data changes in a difference bitmap. The CA manager detects the
status change and outputs a message to syslog. If a host A user has
initiated a monitoring command, a message is displayed on the client’s
screen.
Link
failure
S-VOL
failure
Disconnected
Continue (regression)
Host A
Host B
P
vol
S
vol
Host A
Host B
P
vol
S
vol
Host A
Host B
P
vol
S
vol
Continue (regression)
pairsplit -S
paircreate
c
d
e Entire copy
S-VOL goes down.
S-VOL recovers.
Host A
Host B
P
vol
S
vol
Host A
Host B
P
vol
S
vol
Host A
Host B
P
vol
S
vol
pairresync
c
d
e Difference
Recovery
Mirroring state
Regression state
Recovery state