HP 3PAR InForm OS 3.1.1 Concepts Guide
Glossary
Access Guard A software component that provides volume security at logical and physical levels. Access Guard
is part of the HP 3PAR OS Software Suite.
active VLUN The pairing of a virtual volume and a LUN so the host can access its virtual volume and I/O
writes can be saved to the virtual volume. The VLUN parameters determine whether a virtual
volume is expressed as an active VLUN. VLUNs that are not active will not communicate with the
storage system.
admin volume The base volume that is used by the system to store administration data such as the system event
log. The admin volume is created as part of the system installation and setup process.
AL_PA Arbitrated Loop Physical Address. A unique 8-bit value used to identify Fibre Channel devices
on an arbitrated loop.
alert A system event that requires the immediate attention of the user and might also require user
intervention.
alert pane Area at the bottom of the HP 3PAR Management Console main window that displays information
about system alerts.
allocation limit User-defined threshold that can be set for Thinly-Provisioned Virtual Volumes and fully-provisioned
virtual volumes to cap their potential size.
allocation warning User-defined threshold that can be set for Thinly-Provisioned Virtual Volumes and fully-provisioned
virtual volumes to alert users when the volumes reach a certain size.
availability Level of fault-tolerance for a logical disk. For example, magazine-level availability means that the
logical disk can tolerate a drive magazine failure. Cage-level availability means that the logical
disk can tolerate a drive cage failure.
base volume A Thinly-Provisioned Virtual Volume (TPVV) or fully-provisioned virtual volume that has been
copied.
battery tray An enclosure that inserts into an EIA-standard rack to house a maximum of four battery backup
units.
BBU Battery Backup Unit. A unit containing two batteries. Each Battery Backup Unit supplies two
controller nodes with enough current to write the cache to ATA disks if power is interrupted.
cabinet An enclosure that houses the components of a system. A cabinet is made up of a frame on four
wheels, cosmetic panels, a rear door, an EIA-standard rack, PDUs, power cords, and bezels.
child volume A virtual volume (virtual or physical copy) created from a parent volume.
chunklet A block of contiguous storage space on a physical disk. On F-Class and T-Class systems, all
chunklets are 256 MB. On HP 3PAR 10000 systems, all chunklets are 1 GB.
chunklet logging The process of writing data to a log rather than a chunklet when a chunklet is unavailable (for
example, when the disk is not ready). If the chunklet becomes available, the system places the
chunklet in playback mode, reads the logged data, and writes the data to the chunklet.
classes of service The characteristics and guarantees of the transport layer of a Fibre Channel circuit. These classes
include connection services (Class 1), guaranteed frame delivery with end-to-end flow control
(Class 2), and packetized frame datagrams (Class 3).
clean chunklet A chunklet that is set to all zeros, and therefore does not contain any data.
cluster A group of controller nodes connected via the same system backplane. The nodes in a cluster
operate as a unified system, separate from any other clusters that may share the same service
processor.
CMP Cache Memory Page. A 16 KB block of control cache memory where I/O requests are stored.
component
indicator
HP 3PAR Management Console alert pane icon that represents a logical or physical system
component.
control cache Memory modules that support the microprocessors located in a controller node.
control cache
DIMM
A single control cache memory module.
74 Glossary