Spectra Logic Spectra nTier700, Installation Manual

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Glossary of Terms – P
111
P
package A collection of firmware files that are bundled together to simplify the
installation of firmware upgrades.
parity check
A process that enables checking the integrity of the redundant data on
fault-tolerant arrays, such as RAID 6. Parity checking on a logical drive
recalculates the parity of data stripes in each of the logical drive’s RAID
strip sets and compares it with stored parity. When a discrepancy is
discovered, an error is reported and the new correct parity is substituted
for the stored parity.
R
RAID
Redundant Array of Independent Disks. A method of combining several
hard disk drives into one logical unit or virtual disk (two or more disks
grouped together to appear as a single device to the host system). RAID
technology was developed to address the fault-tolerance and
performance limitations of conventional disk storage. Depending on
how data is written to the disk array (typically referred to as the RAID
level), RAID increases data integrity, fault-tolerance, throughput, or
capacity, as compared with single drives.
RAID controller
A controller used to manage the disk drives in a RAID array. The RAID
controller manages how data is distributed across the disks in the array
based on the RAID level.
RAID level
A RAID level defines how data is written to the disk drives that make up
a RAID array. You can configure only one RAID level across each
volume group. Each volume group stores its own redundancy data. The
capacity of the volume group is the aggregate capacity of the member
drives, minus the capacity reserved for redundancy data. The amount of
capacity needed for redundancy data depends on the RAID level used.
RAID 6
Uses block-level striping with two independent blocks of parity data per
block distributed across all member disks. A RAID 6 volume can
continue to execute read and write requests to all of virtual disks on the
array even when two concurrent disk failures occur.
RMA
Return Materials Authorization. Required by Spectra Logic for the repair
or exchange of any covered Spectra Logic nTier700 VTL components.