Huawei OceanStor Dorado V3 Series Parts Replacement page 225

OceanStor Dorado V3 Series
Parts Replacement
Trim
U
User interface
W
Wear leveling
Working controller
Write Amplification
Write amplification factor
Write back
Write Once Read Many
Write through
Z
Issue 05 (2019-01-30)
A method by which the host operating system may inform a
storage device of data blocks that are no longer in use and
can be reclaimed. Many storage protocols support this
functionality via various names, e.g., ATA TRIM and SCSI
UNMAP.
The space where users interact with a machine.
A set of algorithms utilized by a flash controller to distribute
writes and erases across the cells in a flash device. Cells in
flash devices have a limited ability to survive write cycles.
The purpose of wear leveling is to delay cell wear out and
prolong the useful life of the overall flash device.
The controller that reads data from and writes data onto
LUNs or file systems in storage arrays.
Increase in the number of write operations by the device
beyond the number of write operations requested by hosts.
The ratio of the number of write operations on the device to
the number of write operations requested by the host.
A caching technology in which the completion of a write
request is signaled as soon as the data is in the cache. Actual
writing to non-volatile media occurs at a later time. Write
back includes inherent risks: an application will take action
predicated on the write completion signal, and a system
failure before the data is written to non-volatile media will
cause media contents to be inconsistent with that subsequent
action. For these reasons, sufficient write back
implementations include mechanisms to preserve cache
contents across system failures (including power failures)
and a flushed cache at system restart time.
A type of storage, designed for fixed content, that preserves
what is written to it in an immutable fashion. Optical disks
are an example of WORM storage.
A caching technology in which the completion of a write
request is not signaled until data is safely stored on non-
volatile media. Write performance equipped with the write
through technology is approximately that of a non-cached
system. However, if the written data is also held in a cache,
subsequent read performance may be dramatically
improved.
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