Port Active-Active (2PAA) mode, 4-Port Active-
Active (4PAA) mode, or All Ports All LUNs
(APAL) mode.
S
SAN
See “storage area network”.
SAS
Serial Attached SCSI. A serial version of the
SCSI interface. A point-to-point architecture that
uses a disk controller with four or more channels
that operate simultaneously. Each full-duplex
channel, known as a SAS port, transfers data at
1.5Gb/s, 3Gb/s, or 6Gb/s in each direction. SAS
also supports Serial ATA (SATA) drives, which
can be mixed with SAS drives in a variety of
configurations.
SATA
Serial Advanced Technology Attachment. A
connection standard for fixed and removable
hard disk drives.
SCSI
Small Computer System Interface. A collection
of standards and proposed standards for
input/output (I/O) communication, primarily
intended for connecting storage subsystems or
devices to hosts.
self-encrypting disk (SED)
A disk drive with special firmware that allows the
contents to be encrypted without the use of
specialized encryption software. Self-encrypting
disks are required for encrypted arrays to be
created on Nexsan E-Series storage systems.
SFP
Small Form-factor Pluggable. A type of gigabit
interface converter (GBIC) in a compact form
factor. The Fiber Channel ports or 10Gb iSCSI
ports on Nexsan storage devices are SFPs.
Shell Extensions
One of six Nexsan Storage Tools. Shell
Extensions adds an extension to the Windows
shell to provide information about the Nexsan
storage system associated with a particular disk
drive.
Single Controller Mode
A system mode for Nexsan storage systems. In
this mode, only one RAID controller is active,
and failure of this controller makes all arrays and
volumes inaccessible.
SMTP
Simple Mail Transfer Protocol. An Internet
standard for electronic mail (email) transmission
across TCP/IP networks.
snapshot
A “picture” of the data and state of a volume at a
particular point in time using a copy-on-write
function to capture only data that has changed
since the last snapshot. Snapshots can be used
for many purposes, including backups, restores,
and “sandboxing”.
SNMP
Simple Network Management Protocol. An
Internet-standard protocol for managing devices
on TCP/IP networks. SNMP is based on the
manager/agent model and consists of an
SNMP manager, an SNMP agent, a
Management Information Base, managed SNMP
devices, and the network protocol.
SNMP agent
Provides the interface between the
SNMP manager and the physical devices being
managed. Allows network management stations
to retrieve or set the values various management
objects (attributes) that are applicable to the
networking environment by referencing their
Object Identifiers.
SNMP manager
A software application or suite of software
applications that monitor and control managed
devices in an SNMP environment.
SNTP
Simple Network Time Protocol. One of two
protocols for synchronizing a Nexsan storage
system’s internal clock with that of a time server.
Glossary
Nexsan High-Density Storage
User Guide
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