DATOptic ARC-1680 Series - Manual (Page 137)

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WEB BROWSER-BASED CONFIGURATION
• HDD Read Ahead Cache
Allow Read Ahead (Default: Enabled)—When Enabled, the
drive’s read ahead cache algorithm is used, providing maximum
performance under most circumstances.
• Volume Data Read Ahead
The volume read data ahead parameter specifies the controller
firmware algorithms which process the Read Ahead data blocks
from the disk. The Read Ahead parameter is normal by default.
To modify the value, you must set it from the command line us-
ing the Read Ahead option. The default normal option satisfies
the performance requirements for a typical volume. The disabled
value implies no read ahead. The most efficient value for the
controllers depends on your application. Aggressive read ahead
is optimal for sequential access but it degrades random access.
• HDD Queue Depth
This parameter is adjusted the queue depth capacity of NCQ
(SATA HDD) or Tagged Command Queuing (SAS) which trans-
mits multiple commands to a single target without waiting for
the initial command to complete.
• Empty HDD Slot LED
The firmware has added the "Empty HDD Slot LED" option to
setup the fault LED light "ON "or "OFF" when there is no HDD
installed. When each slot has a power LED for the HDD installed
identify, user can set this option to "OFF ". Choose option "ON",
the SATA RAID controller will light the fault LED; if no HDD
installed.
• SES2 Support
If your SAS backplane doersn't implement the correct SES2
function, you can disable the SES2 support on controller. Con-
troller will use SMP (only monitor PHY not environment) to com-
municate with SAS backplane, but you will be not able to moni-
tor the backplane information.
• SAS Mux Setting (ARC-1680 Only)
The function is only for ARC-1680 Intel SAS controller limitation
of auto configuration of CH5-8 for internal or external. If there
is no linkage at the beginning power on stage, some SAS HDDs