Areca 24/4 Internal/External Port Pcie 3.0 12 Gb/s SAS/SATA Raid Controller 2Gb Cache - Manual (Page 189)

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WEB BROWSER-BASED CONFIGURATION
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 playout 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 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 command sorting method. The default sorting meth-
od is helpful for normal applications, but not useful for AV
applications, so we have defined three different sorting meth-
ods for these special applications. To decide how to optimize AV
stream recording parameter, you need to adjust the Optimize
AV Recording, and Write Buffer Threshold during runtime.
• Read Performance Margin
The “Read Performance Margin” is for controller to reserve n%
read margin during AV stream recording.
• Write Performance Margin
The “Write Performance Margin” is for controller to reserve n%
write margin AV stream recording.
AJA Mode Usage:
1. Controller needs to reboot when you adjust the following set-
tings.
(1). Optimize For AV Recording: change any setting
(2). Read Performance Margin : No <-> X%
(3). Write Performance Margin : No <-> X%