User's Manual
2-16 Chapter 2: RAID conguration
12. Select a second drive group from the Array With Free Space drop-down list,
and click Add to SPAN.
Both drive groups display in the right frame under Span.
13. If there are additional drive groups with two drives each, you can add them to
the virtual drive.
14. When nish, click Next. The Virtual Drive Denition screen appears.
You can use this screen to select the RAID level, strip size, read policy, and
other attributes for the new virtual drives.
The WebBIOS Conguration Utility displays the maximum available capacity
while creating the RAID 10 drive group. In version 1.03 of the utility, the
maximum size of the RAID 10 drive group is the sum total of the two RAID 1
drive groups. In version 1.1, the maximum size is the size of the smaller drive
group multiplied by two.
15. Change the virtual drive options from the defaults listed on the screen as
needed.
Here are brief explanations of the virtual drive options:
• RAID Level: The drop-down menu lists the possible RAID levels for the
virtual drive. Select RAID 10.
• Strip Size: The strip size species the size of the segment written to
each disk in a RAID conguration. You can set the strip size up to 1 MB.
A larger strip size produces higher read performance. If your computer
regularly performs random read requests, choose a smaller strip size.
The default is 256 KB.
• Access Policy: Select the type of data access that is allowed for this
virtual drive:
◊ RW: Allow read/write access. This is the default.
◊ Read Only: Allow read-only access.
◊ Blocked: Do not allow access.
• Read Policy: Specify the read policy for this virtual drive:
◊ No Read Ahead: This disables the read ahead capability.
◊ Always Read Ahead: This enables read ahead capability, which
allows the controller to read sequentially ahead of requested data and
to store the additional data in cache memory, anticipating that the data
will be needed soon. This speeds up reads for sequential data, but
there is little improvement when accessing random data. This is the
default.
• Write Policy: Specify the write policy for this virtual drive:
◊ Write Through: In Write Through mode, the controller sends a data
transfer completion signal to the host when the drive subsystem has
received all of the data in a transaction.