redundancy In a redundant system, if you lose par t of the system, it can continue to operate.
For example, if you have two power supplies with one that takes over if the other
one dies, that’s redundancy.
secondary node A computer (node) that provides secondary administrating and control for
backup and restore operations on a server cluster, and provides additional
storage and multi-pathing capabilities on the system. When configuring the
VLS300, designate the secondary node as such using the letter “s”. On the
VLS300, nodes 1–7 are secondary nodes.
secure sockets
layer (SSL) certifi-
cate
A protocol designed to enable applications to transmit information b ack and
forth securely. Applications that use this protocol inherently know how to give
and receive encryption keys with other applications, as well as how to encrypt
and decrypt data sent b et ween the two.
Some applications that are configuredtorunSSLincludewebbrowserslike
Internet Explorer and Netscape, mail programs like GroupWise, Outlook, and
Outlook Express, FTP (file transfer protocol) programs, etc. These programs are
automatically able to receive SSL connections.
To send an SSL connection, however, or to op en a secure connection, your
application must first have an encryption key assigned to it by a Certification
Authority. Once it has a unique key of its own, you can establish a secure
connection with every other app lication that ca n "speak" the SSL protocol.
serial ATA (SATA )
disk
The evolution of the ATA (ID E ) interface that changes the physical architecture
from parallel to serial and from primary-secondary (master-slave) to
point-to-point. Unlike parallel ATA interfaces that connect two drives; one
configured as primary (master), the other as secondary (slave), each SAT A
drive is connected to its own interface .
simple network
management pro-
tocol (SNMP)
A widely used net work monitoring and control protocol. Data is passed from
SNMP agents, which are hardware and/or software processes reporting activity
in each network device (hub, router, bridge, etc.) to the workstation console
used to oversee the network. The agents return information contained in a MIB
(Management Information Base) , which is a data structure that defines what is
obtainable from the device a nd what c an be controlled (turned off, on, etc.).
small computer
systems interface
(SCSI)
A standard, intelligent parallel interface for attaching peripheral devices to
computers, based on a device independent protocol.
storage area net-
work (SAN)
A c entrally managed n et work that allows any-to-any interconnection of servers
and storage systems.
storage pool Multiple disk arrays logically grouped together from which the dynamic
disk filesystem allocates storage. The disk arrays in a VLS are automatically
configured into one storage array.
tape drive (1) A device that reads data from a nd writes data onto tape.
(2) A software emulation of a tape drive is called a virtual tape drive.
virtual tape Also known as a piece of virtual media or a VLS cartridge. A disk drive buffer
that emulates one physical tape to the host system and appears to the host
backup application as a physical tape. The same application used to back up
to tape is used, but the data is stored on disk.
Data can be written to and read from the virtual tape, and the virtual tape can
be migrated to physical tape.
virtual tape drive An emulation of a physical transport in a virtual tape library that looks like a
phys ical tape transport to the host backup application. The data written to the
virtual tape drive is really being written to disk.
See also virtual tape library.
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Glossary
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