Guidelines for Protecting Data using HP StorageWorks Storage Mirroring with Volume Shadow Copy Service (VSS) (T2558-96332, March 2009)

Figure 6 SAMPLE_TASK.TXT file used in DOSNAPSHOT.BAT
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Figure 7 SAMPLE_SNAPSHOTCOMMAND..BAT file used in TASK.TXT
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Setting up data-consistent synchronous snapshots
For this strategy to work, you will have to initiate snapshots manually on both the source and target
using either the Storage Mirroring in-band control feature or the Windows Task Scheduler.
To ensure that all data is committed to the database and that the data is in a data-consistent state,
you will need to stop the database service. With task command processing, you can stop the source
service just long enough to identify the stopped point in time as a data-consistent state, insert a task
at that point into the Storage Mirroring replication queue to trigger a snapshot on the source and/or
target, and then restart the service. Here is how the process would work:
1. Storage Mirroring and an application are both running on the source. Only Storage Mirroring
is running on the target.
2. The application data is changing on the source and Storage Mirroring is capturing those data
changes and transmitting them to the target.
3. A script is launched (either manually or perhaps scheduled by the Windows Task Scheduler) that
stops the application service on the source, pauses to give the service time to shut down and
write the data to disk, initiates a Storage Mirroring task command, and then restarts the applic-
ation service on the source.
4. The Storage Mirroring task command is processed immediately on the source, initiating snapshot
creation on the source server. Then, the command is transmitted inline with the source replication
data to the target.
Sample Implementation22