HP StorageWorks Storage Mirroring user's guide (T2558-96073, February 2008)

16 - 17
Failover manual intervention
If Manual Intervention is enabled, the Failover Control Center will prompt you when a failure occurs.
Click
Cancel to abort the failover process. If necessary, you can initiate failover later from the Failover Control Center. Click
OK to proceed with failover.
You will be prompted to specify what data you want to use on the target.
Select an option based on the table below. You may want to check the amount of data in queue on the target by reviewing
the Storage Mirroring Performance Monitor or DTStat.
NOTE: If the Failover Control Center is not running at the time the failure occurs, the manual intervention dialog box
will appear the next time the Failover Control Center is started.
When a failure occurs, an alert is forwarded to the Windows Event Viewer. You can then start the Failover
Control Center and respond to the manual intervention prompt.
If SNMP is installed and configured, an SNMP trap is also generated. When using a third-party SNMP manager,
an e-mail or page can be generated to notify you of the failure.
Target Data
State at
Failover
Description Advantages Disadvantages
Apply Data in
Target Queues
Then Failover
All of the data in the target queue will be
applied before failover begins.
All of the data that the
target has received will
be applied before
failover begins.
Depending on the
amount of data in
queue, the amount of
time to apply all of the
data could be lengthy.
Discard Data in
Target Queues
and Failover
Immediately
All of the data in the target queue will be
discarded and failover will begin immediately.
Failover will occur
immediately.
Any data in the target
queue will be lost.
Revert to Last
Good Snapshot if
Target Data is
Bad
If the target data is in a bad Storage Mirroring
state, Storage Mirroring will automatically
revert to the last good Storage Mirroring
snapshot before failover begins. If the target
data is in a good state, Storage Mirroring will
not revert the target data. Instead, Storage
Mirroring will apply the data in the target
queue and then failover.
If there are no snapshots available, this option
will be disabled.
Good data on the
target is guaranteed to
be used.
If the target data state is
bad, you will lose any
data between the last
good snapshot and the
failure.