Specifications

SCSI to SATA RAID Subsystem | Administrator’s Manual Terminal Operation | en 93
Bosch Security Systems F.01U.027.802 | V1 | 2006.11
As one of the submenus in “Caching Parameters,” this option controls the cached write policy.
Choose Caching Parameters, then press [ENTER]. Select Write-Back Cache, then press
[ENTER]. “Enabled” or “Disabled” will display the current setting with Write-back caching.
Choose Yes in the dialog box that follows to confirm the setting.
Write-back caching can dramatically improve write performance by caching the unfinished
writes in memory and letting them be committed to drives in a more efficient manner. In the
event of power failure, a battery backup module can hold cached data for days.
7.2.5 Periodic Cache Flush
Fig. 7.4 Periodic Cache Flush Page
If Write-back caching is preferred for better performance yet data integrity is also a concern,
e.g., no battery protection, the system can be configured to flush the cached writes at preset
intervals.
Note that the “Continuous Sync” option holds data in cache for as long as necessary to com-
plete a write operation and immediately commits it to hard drives if it does not come in a
series of sequential write requests.
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NOTICE!
• If the size of an array is larger than 16TB, only the optimization for sequential I/O can be
applied. Since a logical drive of this size may not be practical, there is actually no limita-
tion on the combination of optimization mode and array capacity.
• Every time you change the Caching Parameters you must reset the controller for the
changes to take effect.
• The Adaptive Write Policy is applicable to subsystems working under normal conditions.
If, for example, a drive fails in an array, the firmware automatically restores the array’s
original write policy.