Fault Tolerance - Hitachi AMS 2000 User Manual

F
failover
The automatic substitution of a functionally equivalent system
component for a failed one. The term failover is most often applied to
intelligent controllers connected to the same storage devices and host
computers. If one of the controllers fails, failover occurs, and the
survivor takes over its I/O load.
fallback
Refers to the process of restarting business operations at a local site
using the P-VOL. It takes place after the storage systems have been
recovered.

Fault tolerance

A system with the ability to continue operating, possibly at a reduced
level, rather than failing completely, when some part of the system
fails.
FC
See Fibre Channel.
Fibre Channel
A gigabit-speed network technology primarily used for storage
networking.
firmware
Software embedded into a storage device. It may also be referred to as
Microcode.
full duplex
The concurrent transmission and the reception of data on a single link.
G
Gbps
Gigabit(s) per second.
granularity of differential data
Refers to the size or amount of data transferred to the S-VOL during an
update cycle. Since only the differential data in the P-VOL is transferred
to the S-VOL, the size of data sent to S-VOL is often the same as that of
data written to the P-VOL. The amount of differential data that can be
managed per write command is limited by the difference between the
•
A B C D E F
Glossary–6
Hitachi AMS 2000 Family TrueCopy Extended Distance User Guide
G I L M
H J K
P R S T
N O Q
V W
U X Y Z