Quick Integration Guide

Intel® RAID SSD Cache Controller RCS25ZB040/RCS25ZB040LX Quick Installation Guide 15
Ahead: Enable read-ahead capability, which permits 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 setting speeds up
reads for sequential data, but little improvement exists when accessing random
data.
— Write Policy: Specify the write policy for this virtual drive.
WBack: In Writeback mode, the controller sends a data transfer completion
signal to the host when the controller cache has received all of 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 drive subsystem has received all of the data in a
transaction. This setting is the default.
Write Back with BBU: Select this mode if you want the controller to use
Writeback mode, but the controller either has no battery backup unit (BBU) or the
BBU is bad. If you do not choose this option, the controller firmware
automatically switches to Writethrough mode if it detects a bad or missing BBU.
Note: You can use Writeback mode with or without a battery. You should use either a
battery to protect the controller cache or an uninterruptible power supply
(UPS) to protect the entire system. If you do not use a battery or a UPS, and a
power failure occurs, you risk losing the data in the controller cache.
Although you can enable or disable the disk cache, you should disable it. If
you enable the disk cache, the drive sends a data transfer completion signal to
the controller when the drive cache has received all the data in a transaction.
However, the data has not been actually transferred to the disk media, so you
risk losing the data in the disk cache if a power failure occurs. The data is
unrecoverable.
— IO Policy: The IO policy applies to reads on a specific virtual drive. It does not
affect the read-ahead cache.
Direct: 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 setting is the default.
Cached: Reads are buffered in cache memory before they are sent to the host.
— Drive Policy: Specify the drive cache policy.
Enable: Enable the drive cache.
Disable: Disable the drive cache.
NoChange: Leave the current drive cache policy as is. This setting is the default.
— Disable BGI: Specify the background initialization status.
No: Leave background initialization enabled. A new configuration can be
initialized in the background while you use WebBIOS to perform other
configuration tasks. This setting is the default.
Ye s: Select Yes if you do not want to allow background initializations for
configurations on this controller.
— Select Size: Specify the size of the virtual drive or drives in MB, GB, or TB.
Usually, this size would be the full size for RAID 1 shown in the Configuration