Technical Product Specification

Intel® RAID Controller RS2WC080 and RS2WC040 TPS RAID Functionality and Features
Revision 1.0
Intel Order Number E64400-001
21
The drive cache is managed through a user-configurable RAID controller option.
Table 13 Cache Policies
Array Cache Policy Cache Option Description
Cache Policy Direct I/O No cache is involved for both reads and writes. The data is transferred
directly from host to disk and from disk to host. Cache I/O mode is
NOT available.
Read Policy No Read Ahead The controller does not use read-ahead.
Write Policy Write Through The controller sends a data transfer completion signal to the host after
the disk subsystem receives all the data in a transaction and the data
is successfully written to disk. Write Back mode is NOT available.
No change Keep the cache setting in the hard drive as default.
Enable Enable the cache setting in the hard drive.
Hard Drive Cache
Disable Disable the cache setting in the hard drive.
4.3.3 Strip Size
The strip size determines the size of each data strip on each hard drive. The options are 8, 16,
32 and 64KB. The strip size is set when the virtual drive is created. It cannot be changed
without removing the virtual drive configuration and all data contained on the virtual drive.
4.3.4 Hot-spare Drives
Hot-spare drives are designated to automatically replace a failed drive. Hot-spare drives must
be the same size or larger than the drives they will replace. They can be designated as a private
hot-spare drive assigned to one virtual drive, or they may be a global hot-spare that is assigned
to all virtual drives attached to the RAID controller. Hot-spare drives can be designated using
the Intel
®
RAID BIOS Console 2 utility, the Intel
®
RAID Web Console 2 utility, or the command
line utility.
4.3.5 Hot-plug Drive Support
Hot-plug support allows hard drives to be inserted or removed without rebooting the system, as
long as both the hard drive and server system backplane support hard drive hot-plug functions.
The RAID controller immediately recognizes when a drive is removed and sets the virtual status
to “Missing” until an I/O to the drive fails. The drive status then changes to “Failed.”
A drive inserted into an attached intelligent enclosure is recognized as present. A drive inserted
into an attached non-intelligent enclosure may require a bus scan before it is detected. Hot plug
of new drives is supported in both intelligent and non-intelligent enclosures.
Note: Auto rebuild is not supported for hot-plugged drive until a manual selection is made by
users. As part of JBOD implementation for Intel
®
RAID Controller RS2WC080 and RS2WC040,
all new drives that are hot-plugged will automatically become JBOD. Users need to manually
move the JBOD drive to Unconfigured Good and auto rebuild starts after that.