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HP SAN Virtualization Services Platform User Manual

Page 386

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mirroring

The creation and continuous updating of one or more redundant copies of data,
usually for the sake of fault or disaster recovery.

OpenVMS Unit ID

Abbreviated as OUID. A storage element identifier that is necessary for hosts
running OpenVMS to interact with the storage elements presented to them. This
identifier is relevant to virtual disks, snapshots, and synchronous mirror groups.

passive path

A path that must have some operation (for example, a SCSI start unit command
that is issued by the server) performed on it to make it active.
See also

active/active RAID

,

active/passive RAID

, and

secondary path

.

patch file

Incremental update to an existing system image.

persistent
reservation

A mechanism for the resolution of dynamic SCSI contention in systems with
multiple initiator ports accessing a logical unit, whereby a single initiator port
or a set of initiator ports can reserve the logical unit indefinitely. While reserved,
the storage device server rejects all commands for that logical unit from any other
initiator ports.

personality

The way in which a DPM exposes LUNs to the hosts that use them. Exposing a
LUN with the correct personality (such as HP EVA VS-ALUA or HP EVA MS-DPM)
for the hosts enables features such as failover and failback between DPMs in
conjunction with the appropriate multipath software running on the host. See the
HP StorageWorks SAN Virtualization Services Platform Manager User Guide
for a list of personalities used with SVSP.

physical disk

A disk device that can be discovered and managed by VSM.

PiT

Point-in-Time. A VSM term denoting an entity created by a snapshot that represents
the freezing of a virtual disk’s data at a particular time and the redirection of
any further modifications to the virtual disk’s data to a new virtual disk, called a
temporary virtual disk.

POST

Power-on Self Test. The diagnostic sequence executed by devices during system
startup.

primary path

For an active/active or active/passive device, a path belonging to the set of
paths that are active by default, as viewed by the server.
See also

active/passive RAID

,

active path

, and

secondary path

.

PSC

Physical storage container. A path from a DPM to a back-end LU. There are eight
PSCs between any two DPM initiator ports and a back-end LU presented to the
domain by an eight-port storage array (for example, an HP EVA8100).

SAN

Storage Area Network. A network specifically dedicated to the task of transporting
data between storage systems and servers. SANs are traditionally connected
over FC networks but have also been built using iSCSI technology.

secondary path

For an active/passive device, the set of paths that are passive by default.
See also

active/passive RAID

,

passive path

, and

primary path

.

setup virtual disk

A virtual disk that contains the virtualized VSM configuration for the SVSP domain,
including, for example, information about storage pools and virtual disks defined
on the domain.

Glossary

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