RAID Xanadu User Manual page 77

Notes on using snapshot function
Update difference management information for data managed by the snapshot facility is in cache
memory.
If update difference management information in cache memory is volatilized due to power-off in
which the disk array unit battery backup time is exceeded when power to the disk array unit was
disconnected by performing the procedure in 6.2 "Power-off Procedure", the next time the disk
array unit starts, it copies the update difference management information from disk drives to cache
memory.
Because of this, the startup time of the disk array unit is delayed approximately 10 seconds per TB
of update differences.
Note: If update difference management information in cache memory is volatilized due to power-
off in which the battery backup time is exceeded when power to the disk array was
disconnected without performing the procedure in 6.2 "Power-off Procedure", the next time
the disk array unit starts, it refreshes update difference management information from disk
drives and copies it to cache memory.
The startup time of the disk array unit in this case is delayed approximately 10 minutes per
TB of update differences.
Notes on using DynamicDataReplication/RemoteDataReplication
Update difference management information (= storage system information) for data managed by
the data replication function is in cache memory.
If storage system information in cache memory is volatilized due to power-off in which the disk
array unit battery backup time is exceeded when power to the disk array unit was disconnected by
performing the procedure in 6.2 "Power-off Procedure", the following matters require attention.
Note: DynamicDataReplication/RemoteDataReplication are functions of the Xanadu.
Main Operating State
Separate state
Replicate state
Restore state
Synchronized State
Separated state Entire area is differences. State does not change.
Separating Changes to FAULT state and copying is halted.
Entire area is differences and Replicate is automatically
Replicating
tried again from the beginning.
Synchronous state State does not change.
Restoring Entire area is differences and Replicate is automatically
tried again from the beginning.
Synchronous state
State does not change.
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Pair State
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