Asus PIKE 2008/IMR - Manual (Page 24)

2-10 Chapter 2: RAID configuration
3. When you have finished selecting drives for the drive group, click Accept DG.
4. Click Next. The Span Definition screen appears. Select one of the available
drive groups, and then click Add to SPAN.
5. When finish, click Next. The Virtual
Drive Definition screen appears, as
shown in the right figure. You use
this screen to select the RAID level,
strip size, read policy, and other
attributes for the new virtual drives.
6. 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 0.
• Strip Size: The strip size specifies the size of the segment written to
each disk in a RAID configuration. You can set the strip size up to 64 KB.
A larger strip size produces higher read performance. If your computer
regularly performs random read requests, choose a smaller strip size.
The default is 64 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:
◊ Normal: This disables the read ahead capability. This is the default.
• Write Policy: Specify the write policy for this virtual drive:
◊ Write Through: In Writethrough mode the controller sends a data
transfer completion signal to the host when the disk subsystem has
received all the data in a transaction. This is the default.
• IO Policy: The IO Policy applies to reads on a specific virtual drive. It
does not affect the read ahead cache.
◊ Direct: In direct I/O mode, reads are not buffered in cache memory.
Data is transferred to the cache and the host concurrently. If the same
data block is read again, it comes from cache memory. This is the
default.