HP StorageWorks 12000 User Manual page 252

on multiple disks, I/O operations can overlap in a balanced way, improving
performance.
RAID1-level data A RAID that consists of at least two drives that use mirroring (100 percent
storage duplication of the storage of data). There is no striping. Read performance is
improved since either disk can be read at the same time. Write performance is
the same as for single disk storage.
RAID5-level data A RAID that provides data striping at the byte level and also stripe error correction
storage information. RAID5 configurations can tolerate one drive failure. Even with a
failed drive, the data in a RAID5 volume can still be accessed normally.
RAID6-level data A RAID that provides data striping at the byte level and also stripe error correction
storage information. RAID6 configurations can tolerate two drive failures. Even with two
failed drives, the data in a RAID6 volume can still be accessed normally. RAID6
read performance is similar to RAID5, since all drives can service read operations,
but the write performance is lower than that of RAID5 because the parity data
must be updated on multiple drives.
redundancy In a redundant system, if you lose part 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.
replication The process of writing data to virtual tape, and after the backups are complete,
writing the data to another virtual tape, known as the replication target, over the
LAN/WAN. Similar to automigration.
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.
SSL certificate Secure Sockets Layer certificate. A protocol designed to enable applications to
transmit information back 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 between the two.
Some applications that are configured to run SSL include web browsers like
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 open 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 application that can "speak" the SSL protocol.
SATA Serial Advanced Technology Attachment.
SCSI Small Computer Systems Interface. A standard, intelligent parallel interface for
attaching peripheral devices to computers, based on a device-independent
protocol.
SNMP Simple Network Management Protocol. A widely used network 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,
and so on) 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 and what can
be controlled (turned off, on, and so on).
252 Glossary