Intel SE8500HW4 - Manual (Page 82)

System BIOS Intel® Server Board Set SE8500HW4
Revision 1.0
Intel order number D22893-001
70
Table 39. Memory Hot Plug Support Under Different Memory Modes
Memory Hot Plug Operation Maximum
Compatibility
Maximum
Performance
Memory
Mirroring
Memory
RAID
Hot-add Supported Supported
Hot-replace Supported Supported
Hot-upgrade Supported
10.1.1 Sparing
Sparing allows for memory to be set aside to replace memory under use when a DIMMs
correctable error count has reached a specified threshold. Unlike mirror or RAID configurations,
spared memory configurations do not provide redundant copies of memory and the system
cannot continue to operate when an uncorrectable error occurs.
DIMMs in the Intel
®
Server Board Set SE8500HW4 are installed in pairs, and are referred to as
a bank, DIMM_1B and DIMM_1A form one bank, while DIMM_2B and DIMM_2A form another.
A DIMM pair may consist of one rank or two ranks. When the memory mode is maximum
performance or maximum compatibility, the BIOS Setup supports setting one rank aside to
serve as a spare for each Memory Board. When the correctable error rate for a failing rank
exceeds the error threshold for switching to spare, the contents of the failing rank are copied to
the spare rank. At the completion of the copy, the failing rank is disabled and the spare rank is
used in its place. The BIOS reports the failing rank with a SEL event, updates the DIMM error
LED on the Memory Board, and sends memory RAS commands to the BMC to update the
system memory state. The DIMMs with the failed rank are disabled on subsequent boots. The
spare rank is no longer used for spare, but instead used as system memory.
When the BIOS Setup is configured for sparing, the largest rank is chosen to serve as the
spare. This ensures that the contents of any failing rank will fit on the spare rank. The amount of
available memory in the system is reduced by the size of the spare rank. If only one rank is
available on a Memory Board, the system BIOS will not configure this rank as a spare.
Table 40. Memory Modes Supporting Sparing
Memory Mode Support For
Sparing
Maxium Compatibility Yes
Maxium Performance Yes
Memory Mirroring No
Memory RAID No
10.1.2 Maximum Compatibility
The maximum compatibility mode allows the most flexibility in installing DIMMs and Memory
Boards and allows for Memory Boards to be hot added. This memory mode is one-way
interleaved, allows sparing configuration, but results in the lowest performance of the supported
configurations.