Hitachi G1500 - Cache Backup Batteries

Item Description
2 The storage system continues to operate for 20 milliseconds and
detects the po
wer failur
e.
3 The cache memory data and stor
age system conguration ar
e backed
up to the cache ash memory in the cache backup assemblies. If power
is restored during the backup, the backup stops unless the backup
battery capacities are used less than 50%. In case, the system operates
in write-through mode until the batteries are charged enough for a full
backup.
4 Data is stored in the cache ash memory until power is restored, and
then it is written to the drives.
Cache backup batteries
If a power failure occurs, nickel-hydride batteries keep the cache memory active while
the entire storage system conguration and data in the cache are copied to the ash
memory in the cache backup modules. The batteries are located in the cache backup
modules. The
y ar
e fully char
ged at the distribution center wher
e the storage system is
assembled and tested. During shipment, the batteries are disconnected automatically to
prevent any discharging during shipping and storage until the system is installed. During
installation, they are reconnected. The following gure provides an overview of the cache
backup battery.
Note: The stor
age system gener
ates a SIM when the cache backup batteries
ar
e not connected.
Cache backup batteries
Chapter 7: VSP G1x00 and F1x00 batteries
Hitachi Virtual Storage Platform G1000, G1500, and VSP F1500 Hardware Guide 126