Dell 6 series, User Manual

Page: 146 / 160

146
Glossary
N
Non Read Ahead
Non read ahead is a cache read policy. If you select Non read ahead in the BIOS
Configuration Utility, the controller does
not
read sequentially ahead of
requested data and store the additional data in cache memory, anticipating that
the data is needed soon. Non read ahead is most effective when accessing
random data.
Non Redundant Virtual Disk
A non-redundant virtual disk is one which does not have redundant data on
physical disks that can be used to rebuild a failed physical disk. A RAID 0 virtual
disk consists of data striped across the physical disks, without disk mirroring or
parity to provide redundancy. This provides for high data throughput but offers
no protection in case of a physical disk failure.
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.
Dell_PERC6.2_UG.book Page 146 Wednesday, June 24, 2009 6:08 PM