Adaptec 5325301656 - Snap Server 14000 NAS, Руководство администратора

Страница: 214 / 224

200 Snap Server Administrator Guide
POSIX (Portable Operating System
Interface) A set of standard operating system interfaces based on the
UNIX operating system. The need for standardization arose
because enterprises using computers wanted to develop
programs that could run on multiple platforms without the
need to recode. Pre-GuardianOS 5.0 Snap Servers use
Extended POSIX ACLs.
protocol A standardized set of rules that specifies the format, timing,
sequencing, and/or error checking for data transmissions.
public access share A share that allows all users read/write access to the file
system.
quota A limit on the amount of storage space on a volume that a
specific user or NIS group can consume.
RAID (Redundant Array of
Independent Disks) A collection of disk drives that act together as a single
storage system. Different RAID types provide different levels
of data protection.
RAID 0 (Striped) Distributes data evenly among all disks in the array. This
technique, called data striping, results in fast access speeds
because it uses multiple physical devices to store the data.
However, RAID 0 offers no redundancy and does not accept
hot spares. If a single disk drive fails, every file in the RAID
is rendered unavailable.
RAID 1 (Mirrored) Stores data on one disk drive and copies it to another drive
in the RAID. A RAID 1 must contain at least two disk drives:
one for the data space and one for redundancy. Although
the data space in a RAID 1 can never be larger than a single
drive, some administrators prefer to add a third drive (either
as a hot spare or a member) for additional redundancy.
RAID 1 is the most secure method for storing mission-critical
data because there is no catastrophic data loss when a disk
fails. However, RAID 1 is the most expensive and least
efficient storage method.
RAID 5 (Striping with Parity) Distributes data evenly among all disks in the array, and
maintains parity information (error correction data) that
allows the system to recover from a single disk drive failure.
RAID 5 provides the best combination of performance,
usability, capacity, and data protection.
RAID 6 (Striping with Dual Parity) Similar to RAID 5 except that two drives maintain parity
information for greater redundancy. System can recover
from two drive failures. Provides high reliability and data
protection but write performance speed is impacted by the
dual parity drives.
Term Definition