Dell PowerEdge RAID Controller 6i - Manual (Page 144)

144
Glossary
Ns
Acronym for nanosecond(s), one billionth of a second.
NVRAM
Acronym for non-volatile random access memory. A storage system that does
not lose the data stored on it when power is removed. NVRAM is used to store
configuration data on the RAID controller.
O
Offline
A physical disk is offline when it is part of a virtual disk but its data is not
accessible to the virtual disk.
Online
An online device is a device that is accessible.
Online Capacity Expansion
Operation to add capacity to an existing virtual disk by adding an additional
physical disk while the host system is active, and without affecting data
availability.
Operating Environment
An operating environment can include the host system where physical disks are
attached, any I/O buses and controllers, the host operating system and any
additional software required to manage the virtual disk. For host-based arrays,
the operating environment includes I/O driver software for the member disks but
does not include array management software, which is regarded as part of the
array itself.
P
Parity
An extra bit added to a byte or word to reveal errors in storage (in RAM or disk)
or transmission. Parity is used to generate a set of redundancy data from two or
more parent data sets. The redundancy data can be used to rebuild one of the
parent data sets. However, parity data does not fully duplicate the parent data
Dell_PERC6.1_UG.book Page 144 Wednesday, April 15, 2009 4:18 PM