Asus PIKE 1078 - Manual (Page 30)

2-16 Chapter 2: RAID configuration
◊ WBack: In Writeback mode the controller sends a data transfer
completion signal to the host when the controller cache has received
all the data in a transaction. This setting is recommended in Standard
mode.
◊ WThru: 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.
◊ Wrthru for BAD BBU: Select WBack for Write Policy and unselect this
item if you want the controller to use Writeback mode but the controller
has no BBU or the BBU is bad. If you choose this option, the controller
firmware automatically switches to Writethrough mode if it detects a bad
or missing BBU.
• IO Policy: The IO Policy applies to reads on a specific virtual disk. 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.
◊ Cached: In Cached I/O mode, all reads are buffered in cache memory.
• Disk Cache Policy: Specify the disk cache policy:
◊ Enable: Enable the disk cache.
◊ Disable: Disable the disk cache. This is the default.
◊ NoChange: Leave the current disk cache policy unchanged.
• Disable BGI: Specify the background initialization status:
◊ No: Leave background initialization enabled. This means that a
new configuration can be initialized in the background while you use
WebBIOS to do other configuration tasks. This is the default.
◊ Yes: Select Yes if you do not want to allow background initializations
for configurations on this controller.
• Select Size: Specify the size of the virtual disk in megabytes. Normally,
this would be the full size for RAID 5 shown in the Configuration Panel
on the right. You may specify a smaller size if you want to create other
virtual disks on the same disk group.
6. Click Accept to accept the changes to the virtual disk definition, or click Back
to return to the previous settings.
7. Click Next when you are finished defining virtual disks.
The configuration preview screen appears, as shown in the following figure.