Asus LSI SAS3442X-R - Manual (Page 23)

Fusion-MPT Support 2-7
Version 1.1 Copyright © 2006, 2007 by LSI Logic Corporation. All rights reserved.
2.4.6 Media Verification
The firmware supports a background media verification feature that runs
at regular intervals when the IM/IME volume is in optimal state. If the
verification command fails for any reason, the other disk’s data for this
segment is read and written to the failing disk in an attempt to refresh
the data. The current Media Verification Logical Block Address is written
to nonvolatile memory occasionally to allow media verification to continue
approximately where it left off prior to a power-cycle.
2.4.7 Disk Write Caching
The firmware disables disk write caching by default for IM/IME volumes.
This is done to increase data integrity, so that the disk write log stored
in NVSRAM is always valid. If disk write caching were enabled (not
recommended), the disk write log could be invalid.
2.4.8 NVSRAM Usage
The Integrated RAID firmware requires at least a 32K NVSRAM in order
to perform write journaling. Write journaling is used to verify that the
disks in the IM/IME volume are synchronized with each other.
2.5 Fusion-MPT Support
The BIOS uses the LSI Fusion-MPT interface to communicate to the
SAS controller and firmware to enable IM and IME volumes. This
includes reading the Fusion-MPT configuration to access the parameters
that are used to define behavior between the SAS controller and the
devices connected to it. The Fusion-MPT drivers for all supported
operating systems implement the Fusion-MPT interface to communicate
with the controller and firmware.