HP SAN Virtualization Services Platform - Manual (Page 34)

migration A VSM service that migrates virtual disks from one storage pool to another while
the host application remains online.
mirror A VSM service that mirrors virtual disks synchronously and asynchronously.
See also
asynchronous mirroring and synchronous mirroring .
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).
quad A Data Path Module purpose-built ASIC that is capable of directing the data to
and from the hosts. The DPM has four quads, with all capable of communicating
across all ports, although it is desirable to keep traffic within a quad if possible.
Each quad contains two front or host-facing ports, and two back or storage ports.
Each of these ports is capable of a 4 Gbit/s Fibre Channel rate. Therefore, using
additional quads may be necessary as a multiple of that 8 Gbit/s or 6.4 MB/s
rate.
Glossary 34