Grass Valley Network Attached Storage System Serial ATA Network User Guide v.1.0.04 - Manual (Page 134)

RAID Controller Information
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HW
Revision Revision number of the controller hardware.
Sector Size Number of bytes in a sector.
Drive
Stripe Size Drive stripe size.
Read
Ahead Read Ahead improves data retrieval performance because the
controller always reads a full data stripe into cache. If the stripe size is 8KB and
the read request is for 1KB, the controller reads 8KB. If subsequent read requests
are for sequential data, it will already be in cache. Time spent reading the drive is
minimized.
Read
Cache If read cache is enabled, the controller checks cache memory for
the requested data. Only if the data is not in cache does it read the drives. If read
cache is disabled, data is always read from the drives.
Write
Cache If write cache is enabled, the controller saves the data in cache memory and returns
a Command Complete before actually writing the data to the drives. If write cache
is disabled, the controller writes the data to the drives before issuing a Command
Complete. Enabling write cache increases write performance, but introduces some
data vulnerability. If data integrity is the primary consideration, disable write
cache.
Write
Cache
Mirror This feature is available only in a dual controller system, and
enabling it on one controller automatically enables it on the other controller. If
write cache mirroring is enabled, write cache data is duplicated in the cache
memory of each controller. Exactly half of the write segments on each controller
are reserved for the peer controller data. With write cache mirroring enabled, static
cache segment allocation is automatically enabled and cannot be disabled. With
write cache mirroring enabled, write caching is allowed when both controllers are
enabled.
State The state can be Not Present, Failed, Disabled, Enabled, or Resetting.
Peer State For the peer controller, the state can be Not Present, Failed, Disabled, Enabled, or
Resetting. This field may not be present.
Parity
Check If parity check is enabled, the controller performs additional, useful error
reporting. Enabling parity checking decreases performance, so by default it is
disabled.
Drive Start
Time The maximum of.1 second increments that the array waits for a drive to become
ready before turning to the next drive. Default is 10. If this is 0, all drives start
simultaneously. This is not recommended because the power required to start all
drives at once can tax the power supply.
Field Description