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Appendix A Features of Disk Array Unit
1.
Battery Backup
The disk array unit keeps memory data with battery while the power is off.
Accordingly, to make the power off for a period longer than the battery hold period, it is
necessary to make sure that the BAT LED on the controller is off (this indicates that no
data is saved in cache). In addition, pairing must be released during use of DDR (Dynamic
Data Replication).
If the batteries exceed the battery hold period in the backup state, the following operation
will be done. The cache data is lost. The data must be recovered from the backup data
saved in magnetic tapes.
1)
At the first start, the SERVICE LED repeats 5-sec flashing/7-sec OFF. The disk
array unit is not started normally.
2)
The event log contains the following code:
6830 Controller Event
3)
The disk array unit is started normally by turning the array controller off once and
then on again.
2.
Cross Call Feature
The disk array unit contains several features on the cross call.
2.1
Initial Assignment Feature
(1) The path-side controller with a logical disk bound is subject to the assignment of the
logical disk.
If an attempt is made to access to the logical disk from the controller which does not
assign the disk, error 05/04/00 (illegal request - not assigned) is returned. When an
attempt is made to unbind the logical disk from the controller which does not assign
the disk, the same response is returned. However, the changing operation moves the
assignment to the local controller.
(2) The assignment state is retained at re-entry of the power.
This is called the default assignment. In the unbinding, the path free status occurs in
which any controller can access to logical disks. If so, logical disks are undefined for
I/O from the host.
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