Owner's Manual
LSI SAS RAID
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MS-96E0
B-7
LSI SAS RAID
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MS-96E0
2�4 Integrated Mirroring Firmware
This section describes features of the LSI Logic Integrated Mirroring (IM) rmware,
which supports up to two IM volumes per LSI Logic SAS controller.
2�4�1 Host Interface
The IM host interface uses the Message Passing Interface, as described in the Fusion-
MPT Message Passing Interface Specication. Through the Fusion-MPT interface, the
host OS has access to the IM volume as well as the physical disks.
2�4�2 Resynchronization with Concurrent Host I/O Operation
The IM rmware allows Host I/Os to continue on the IM/IME volume while the volume
is being re-synchronized in the background. Resynchronization is attempted after a hot
spare is activated due to a physical device failure, or after a hot swap has occurred to a
physical disk in the IM or IME volume.
2�4�3 Metadata Support
The rmware supports metadata, which describes the IM/IME logical drive congura-
tion stored on each member disk. When the rmware is initialized, each member disk is
queried to read the stored metadata in order to verify the conguration. The usable disk
space for each member disk is adjusted down to leave room for this data.
2�4�4 Hot Swapping
The IM rmware supports hot swapping. The hot-swapped disk is automatically resyn-
chronized in the background, without any host or user intervention. The rmware de-
tects hot swap removal and disk insertion.
Following a hot swap event, the rmware readies the new physical disk by spinning it
up and verifying that it has enough capacity for the mirrored volume. The IM rmware
resynchronizes all hot-swapped disks that have been removed, even if the same disk
is re-inserted. In a two-disk mirrored volume, the IM rmware marks the hot-swapped
disk as the secondary disk and marks the other mirrored disk as the primary disk. The
rmware resynchronizes all data from the primary disk onto the new secondary disk.
2�4�5 SMART Support
The IM rmware enables Mode 6 SMART on the member disks in the mirrored volume.
Mode 6 SMART requires each physical disk to be polled at regular intervals. If a SMART
ASC/ASCQ code is detected on a physical disk in the volume, the rmware processes
the SMART data, and the last received SMART ASC/ASCQ is stored in non-volatile
memory. The IM/IME volume does not support SMART directly, since it is just a logical
representation of the physical disks in the volume.
2�4�6 Hot Spare Disk
One disk can be congured as a global hot spare disk, which protects data on the one
or two volumes congured on the controller. If the IM rmware fails one of the mirrored
disks, the rmware automatically replaces it with the hot spare disk. The IM rmware
then resynchronizes the mirrored data. The IM rmware is automatically notied when