NEC Express5800 Series Maintenance Manual page 97

Chapter 2 Useful Features
7. Select a relevant value for RAID, Units, Size, DWC, RA, and Span by using cursor keys.
Press the <Enter> key to fix the selection to determine each value.
(1) RAID: Specify the RAID level.
Parameter
0
1
The selectable RAID level varies depending on the number of physical devices that configure a
disk array.
(2) Units: Specify the unit (MB, GB, or TB) used in Size field.
(3) Size: Specify the size of the virtual drive. Up to eight Virtual Drives can be created per RAID
Controller.
(4) DWC (Disk Write Cache): Specify the method for writing cached data to the disk.
Parameter
Off
On*
For this server, write back is recommended for good
performance. Note, however, that cached data may be lost
at an unexpected power failure. Selecting write through
degrades performance by approximately 50%.
(5) RA (Read Ahead): Specify whether to use read-ahead.
Parameter
Off
On*
(6) Span: Specify Span.
The server does not use this feature.
Remarks
RAID0
RAID1
Important Screen for RAID5 may appear, but this server does not support RAID5.
Remarks
Write through
Write back
Remarks
Does not perform read ahead.
Performs read ahead.
Express5800/B120f-h Maintenance Guide
* Recommended
* Recommended
4. RAID System Configuration
97