3PAR InForm® OS 2.2.4 Concepts Guide (320-200085 Rev B, March 2009)

GL 9
Glossary
InForm OS Version 2.2.4 3PAR InForm OS Concepts Guide
P
parent volume
A virtual volume from which a virtual or physical
copy is made. See also original parent base
volume.
parity
A data redundancy technique used by some RAID
levels and in particular RAID 5 to provide data
protection on a storage array.
parity set
See RAID 5 set.
parity set position
The group of chunklets that occupy the same
position within a RAID 5 logical disk parity set.
PCI load card
An electronic circuit board that is inserted into a
controller node’s PCI slot. The PCI load card
allows the node to recognize an unoccupied PCI
slot.
PDU
See power distribution unit.
physical copy
A point-in-time copy of an entire virtual volume.
physical copy resynch
See resynchronize.
physical disk
A dual-ported Fibre Channel disk mounted onto
a drive magazine.
physical parent
The source volume for a physical copy.
physical size
The total actual raw storage currently allocated
to a logical disk, as determined by its size and
raid type.
port-presents VLUN template
A VLUN template that allows any host connected
to a particular port to see a virtual volume as a
specified LUN. See also VLUN template.
power bank
A group of four connected AC outlets within the
power distribution unit (PDU). There are two
power banks in each PDU.
power distribution unit (PDU)
A device that takes in AC power from a main
power source (for example, an electrical wall
outlet) and distributes the power to the power
supplies in a storage server.
power supply
A device that converts current from an AC line
into appropriate DC levels and provides that
power to a storage server component.
preserved data
Data that is suspended in the system’s cache
memory due to backend failure.
preserved data logical disks
RAID 10 logical disks created by the system
during initial system setup to store preserved
data. The logical capacity of the preserved data
logical disks is equal to the sum of all data cache
memory of the system.
primary path
Connection between a controller node initiator
port and a physical disk that is used by default.
When the primary path cannot be used (a failure
condition), the secondary path is used. The
primary and secondary paths are not user
configurable and are determined by drive
magazine placement.