NEC NF2300-SE41E User Manual page 49

(2) Notes on turning off AC power
The disk array unit to be connected with the additional disk enclosure periodically
writes data from the cache memory onto a disk. If you turn off the AC power
before completion of write to the disk, the remaining data on the disk is backed up
by the battery backup units.
However, the backup time is limited (4 days if the cache memory has the allowable
maximum capacity and the two battery backup units are fully charged).
securely protect data, turn off the AC power after all the data has been written from
the cache memory in the disk array unit onto the disk. Turn off the AC power
according to the procedure explained in "(3) Turning off AC power".
1. Turn off the host system and the host bus adapter or the FC-AL switch.
Alternatively, offline all the buses connected to the host system that is
connected with the disk array unit.
2. If NEC Storage DynamicDataReplication is used, execute the Unpair
command.
3. Turn on the shut down switch (toggle switch with SHUT DOWN indicated) of
the LAN card in the array controller. (*1)
4. Confirm that [SDN LED] of the LAN card in the array controller is on, and
then turn off the AC power according to the procedure explained in "(3)
Turning off AC power".
[SDN LED] flashes while data remaining in cache memory is being written
onto the disk drive. Do not turn off the AC power while it is flashing. (*2)
Relationship between [SDN LED] states and operations of the disk array unit:
Normal state:
During cache data write onto disk:
Completion of cache data write onto disk: On
Writing cache data onto a disk drive usually takes about 10 minutes and 20
minutes at maximum.
If cache data is not written onto a disk drive normally, the LEDs of the LAN
card enters the following states.
service agent.
RDY LED: On
FLT LED:
SDN LED:
5. Turn off the shut down switch (toggle switch with SHUT DOWN indicated) of
the LAN card in the array controller. (*3)
Flashing
Off
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Off
Flashing
In this case, contact your maintenance
To