Dell FC4500, Hardware Reference Manual

Page: 102 / 110

g-4 EMC Fibre Channel Disk-Array Processor Enclosure (DPE) Hardware Reference
Glossary
N
node Any device with a Fibre Channel interface (such as an HBA in a
server or a storage system’s SP) that connects to a Fibre Channel
loop.
P
PDU (power
distribution unit)
A device for the distribution of ac line power from one inlet to
multiple outlets. Multiple PDUs — in a rackmount cabinet or
deskside storage system — provide higher availability since the
power continues if one PDU (or its ac source, if the PDUs use
separate ac sources) loses power.
physical disk unit Another name for LUN. See LUN (logical unit).
power supply An essential element of the storage-system power supply. A
storage system can have two power supplies, PS A and PS B.
With two, it can survive failure of one supply. You can replace a
power supply under power, without interrupting applications.
PLDA (private loop
direct attach)
profile
A standard for FC-AL disk drives.
R
replace under
power
The storage system provides replace under power capability,
allowing you to replace, for example, a disk module or a fan
module without powering down the storage system.
Applications continue while you replace the failed module.
S
SCSI (small computer
system interface)
A well-known protocol and standard for connecting computers
and peripheral devices. Some Fibre Channel SPs use a Fibre
Channel FC-AL front end to the server and a SCSI back end to the
disk modules. The SPs used in DPEs use the Fibre Channel
protocol throughout. The array uses SCSI protocol over Fibre
Channel.
server In the context of storage systems, a processor that runs an
operating system and uses a disk-array storage system for data
storage and retrieval.
SFF Small Form Factor Committee