Dell PowerEdge RAID Controller 6i - Manual (Page 85)

Configuring and Managing RAID
85
Virtual Disk Management
Creating Virtual Disks
NOTE:
PERC 6 does not support creation of a virtual disk that combines SAS
physical disks and SATA physical disks.
Perform the following steps to create virtual disks.
1 During host system bootup, press when the BIOS banner
displays.
The Virtual Disk Management screen displays. If there is more than one
controller, the main menu screen displays. Select a controller, and press
. The Virtual Disk Management screen displays for the selected
controller.
NOTE:
This procedure describes the BIOS Configuration Utility screens in
Tree View.
2 Use the arrow keys to highlight Controller # or Disk Group #.
Read Policy Read-ahead enables the Read-Ahead feature for the virtual
disk. You can set this parameter to Read-ahead,
No-read-ahead, or Adaptive. The default is No-read-ahead.
Read-ahead specifies that the controller uses Read-Ahead for
the current virtual disk. Read-ahead capability allows the
controller to read sequentially ahead of requested data and
store the additional data in cache memory, anticipating that
the data is required soon.
No-read-ahead specifies that the controller does not use
Read-Ahead for the current virtual disk.
NOTE:
No-Read-Ahead shows higher performance results due to
the effectiveness of hard-drive caching algorithms.
Adaptive specifies that the controller begins using Read-Ahead
if the two most recent disk accesses occurred in sequential
sectors. If all read requests are random, the algorithm reverts to
No-read-ahead; however, all requests are still evaluated for
possible sequential operation.
Table 6-2. Virtual Disk Parameters and Descriptions (continued)
Parameter Description
Dell_PERC6.1_UG.book Page 85 Wednesday, April 15, 2009 4:18 PM