HP StorageWorks Data Replication Manager HSG80 ACS Version 8.7P Configuration Guide (AA-RPHZF-TE, March 2004)
Glossary
248 Data Replication Manager HSG80 ACS Version 8.7P Configuration Guide
QoS
An acronym for Quality of Service in an ATM network. Each virtual connection in an ATM network is set to a
service category. The performance of the connection is measured by the established QoS parameters (outlined
by the ATM Forum).
Performance issues include data rate, cell loss rate, cell delay, and delay variation (jitter).
Categories of ATM service are:
■ Constant Bit Rate (CBR)
■ Variable Bit Rate-Real Time (VBR-RT)
■ Variable Bit Rate-Non-Real Time (VBR-NRT)
■ Available Bit Rate (ABR)
■ Unspecified Bit Rate (UBR)
See also ATM.
RCS
See remote copy sets.
redundancy
The provision of multiple interchangeable components to perform a single function in order to cope with failures
and errors. A RAIDset is considered to be redundant when user data is recorded directly to one member, and all
of the other members and associated parity also are recorded. If a member is missing from the RAIDset, its data
can be regenerated as needed, but the RAIDset is no longer redundant until the missing member is replaced and
reconstructed.
remote copy sets
A feature that allows data to be copied (mirrored) from the originating site (initiator) to a remote site (target).
The result is a mirror copy of the data (remote copy set) at two disparate sites. Used in disaster tolerance (DT)
applications such as the Data Replication Manager.
CLI commands available are: ADD REMOTE_COPY_SETS, SET remote-copy-set-name, SET
controller REMOTE_COPY.
See also disaster tolerance, non-RCS LUN.
remote copy set metadata
Remote copy set metadata describes the remote copy set membership and state. To assist with site failover, this
metadata is located in the mirrored write-back cache on the controller where each member resides. Backup
copies of the metadata reside in the controller NVRAM at each site. Only the initiator modifies the metadata and
ensures all copies are subsequently updated.
replacement policy
The policy specified by a CLI command switch (SET FAILEDSET command) indicating whether a failed disk
from a mirrorset or RAIDset is to be automatically replaced with a disk from the spareset. The two switch
choices are AUTOSPARE and NOAUTOSPARE.
SCSI
An acronym for Small Computer System Interface:
1. An American National Standards Institute (ANSI) interface standard defining the physical and electrical
parameters of a parallel I/O bus used to connect initiators to devices.
2. A processor-independent standard protocol for system-level interfacing between a computer and intelligent
devices, including hard drives, floppy disks, CD-ROMs, printers, scanners, and others.
Refer to http://www.t10.org
for more information.