Compaq StorageWorks Data Replication Manager HSG80 ACS Version 8.5P Operations Guide

Glossary G–5
EMU An acronym for Environmental Monitoring Unit. A piece of hardware that
provides increased protection against catastrophic failures. Some subsystem
enclosures include an EMU which works with the controller to detect
conditions such as failed power supplies, failed blowers, elevated
temperatures, and external air sense faults. The EMU also controls certain
cabinet hardware including DOC chips, alarms, and fan speeds.
external cache battery See ECB.
F_Port A port in a fabric where an N_Port or NL_Port may attach.
See N_Port, NL_Port, and FL_Port.
fabric A network of switches containing a Fibre Channel Arbitrated Loop.
failback The process of restoring data access to the newly-restored controller in a
dual-redundant controller configuration. The failback method (full copy or
fast-failback) is determined by the enabling of the Logging or Failsafe
switches, the selected mode of operation (synchronous or asynchronous), and
whether the failover is planned or unplanned.
See also failover, dual-redundant configuration.
failedset A group of disk drives that have been removed from RAIDsets due to a
failure or a manual removal. Disk drives in the failedset should be considered
defective and should be tested and repaired before being placed back into the
spareset or back in their original locations.
failover The process that takes place when one controller in a dual-redundant
configuration assumes the workload of a failed companion controller.
Failover continues until the failed controller is repaired or replaced.
CLI commands available are: SITE_FAILOVER
See also failback, dual-redundant configuration, planned failover.
Failsafe Locked The failsafe error mode can be enabled by the user to fail any I/O whenever
the target is inaccessible or the initiator unit fails. When either of these
conditions occur, the remote copy set goes into the inoperative (offline) state
and the failsafe error mode is “Failsafe Locked.”
The CLI command SET remote-copy-set-name ERROR_MODE=FAILSAFE
enables this error mode.