DATOptic RM12-S6.TB - Rackmount - Manual (Page 38)

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WEB BROWSER-BASED CONFIGURATION
The Amount of Read Ahead parameter is used to allocate an
amount of memory in the cache memory the frequently ex-
ecuted queries and return the result set back to the host with-
out real disk read execution. Default value is Auto: Controller
will base on the HDD number to set the Amount of Read Ahead
value. You can select between 512KB ~ 16MB.
• Number of AV Stream
RAID controllers are required to have not only the function of
processing ordinary data but also the function of dealing with AV
(audio/video) stream data needing real-time processing. Since
the bus cycle used in RAID controller was designed to transfer
the computer data exactly, it was unsuitable for the transfer
of AV stream needing great band widths. They are required to
do some setting for the handshaking during the processing of
stream data. This setting is an object of transferring stream data
efficiently on an existing RAID controller. Normally you should
not need to modify this value. Default value is 6. You can select
between 6~256.
To decide how to set AV stream play out parameter, you need to
check the Number of Stream, Amount of Read Ahead, and Total
Cache Memory during runtime. You can try to adjust the three
numbers to get the best performance as your requirement.
Number of AV Stream shows the number of stream added to
the system, Amount of Read Ahead shows the Amount of Read
Ahead data taken from the cache without real disk execution,
and total cache memory shows the total available memory being
installed in the RAID controller.
• Optimize AV Recording
AV recording option is for video recording (no time limit), but if
used in normal operation, performance may be degraded. This
new feature there are 4 options; Disabled, Mode1, Mode2 and
Mode 3. Default value is Disabled. Our controller cache uses LRU
method; there have no special memory capacity reserved for
read or write. The Mode 1, 2 and 3 are used to define the com-
mand sorting method. The default sorting method is helpful for
normal applications, but not useful for AV applications, so we
have defined three different sorting methods for these special
applications. To decide how to optimize AV stream recording
parameter, you need to adjust the Optimize AV Recording, and