Installation guide

Chapter 4. Web Browser-Based Configuration

4.8.1.4 SATA NCQ Support

The controller supports both SAS and SATA disk drives. The SATA NCQ allows

multiple commands to be outstanding within a drive at the same time. Drives that

support NCQ have an internal queue where outstanding commands can be

dynamically rescheduled or re-ordered, along with the necessary tracking

mechanisms for outstanding and completed portions of the workload. The RAID

subsystem allows the user to select the SATA NCQ support: “Enabled” or “Disabled”.

4.8.1.5 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.

4.8.1.6 Volume Data Read Ahead

The 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 using

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.

4.8.1.7 HDD Queue Depth

This parameter is adjusted the queue depth capacity of NCQ (SATA HDD) or Tagged

Command Queuing (SAS) which transmits multiple commands to a single target with-

out waiting for the initial command to complete.

4.8.1.8 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

SAS RAID controller will light the fault LED; if no HDD installed.

4.8.1.9 CPU Fan Detection

The "CPU Fan Detection" function is for RAID card only. (Default: Disabled)

4.8.1.10 SES2 Support

If your SAS backplane does not implement the correct SES2 function, you can

disable the SES2 support on controller. Controller will use SMP (only monitor PHY

not environment) to communicate with SAS backplane, but you will be not able to

monitor the backplane information.

4.8.1.11 Max Command Length

Max Command Length is used to set a "best" IO size for the RAID controller.