Lenovo ThinkServer RD230, Руководство пользователя программного обеспечения

Страница: 350 / 364

B-2 Glossary
cache flush
interval A controller property that indicates how often the data cache is flushed.
caching The process of using a high speed memory buffer to speed up a
computer system’s overall read/write performance. The cache can be
accessed at a higher speed than a drive subsystem. To improve read
performance, the cache usually contains the most recently accessed
data, as well as data from adjacent drive sectors. To improve write
performance, the cache may temporarily store data in accordance with
its write back policies.
capacity A property that indicates the amount of storage space on a drive or
virtual drive.
coerced
capacity A drive property indicating the capacity to which a drive has been
coerced (forced) to make it compatible with other drives that are
nominally the same capacity. For example, a 4 Gbyte drive from one
manufacturer may be 4,196 Mbytes, and a 4 Gbyte from another
manufacturer may be 4,128 Mbytes. These drives could be coerced to a
usable capacity of 4,088 Mbytes each for use in a drive group in a
storage configuration.
coercion mode A controller property indicating the capacity to which drives of nominally
identical capacity are coerced (forced) to make them usable in a storage
configuration.
consistency
check An operation that verifies that all stripes in a virtual drive with a
redundant RAID level are consistent and that automatically fixes any
errors. For RAID 1 drive groups, this operation verifies correct mirrored
data for each stripe.
consistency
check rate The rate at which consistency check operations are run on a computer
system.
controller A chip that controls the transfer of data between the microprocessor and
memory or between the microprocessor and a peripheral device such as
a drive. RAID controllers perform RAID functions such as striping and
mirroring to provide data protection. MegaRAID Storage Manager
software runs on ThinkServer SAS controllers.
copyback The procedure used to copy data from a source drive of a virtual drive
to a destination drive that is not a part of the virtual drive. The copyback
operation is often used to create or restore a specific physical