HP ProLiant ML370 G5 Server - Manual (Page 46)

Hardware options installation 46
memory read on one memory board returns incorrect data due to an uncorrectable memory error, the
system automatically retrieves the proper data from the other memory board. A memory board is not
necessarily disabled (thus losing mirroring protection) because of a single uncorrectable error. Mirroring
protection is not lost due to transient and soft uncorrectable errors, resulting in systems that maintain
mirroring protection (and thus improved uptime) unless there is a true FBDIMM failure.
Because both memory boards are active, concurrent reads from both memory boards at the same time are
possible. Therefore, mirroring provides superior read performance compared to all other Advanced
Memory Protection modes.
Mirrored memory allows the server to keep two copies of all memory data on separate memory boards. If
an uncorrectable error is encountered, the proper data is retrieved from the memory board that does not
contain the error. There is no negative performance impact from using mirrored memory.
In addition to general configuration requirements ("
FBDIMM installation guidelines " on page 48 ),
mirrored memory has the following FBDIMM configuration requirements:
• Memory board 1 and memory board 2 must both be populated.
• Memory board 1 and memory board 2 must have identical memory configurations.
• Each bank of memory board 1 must be populated using FBDIMMs with identical HP part numbers to
the corresponding bank of memory board 2.
• Mirrored memory does not support any hot-plug operations.
In mirroring mode, FBDIMMs must be populated as specified in the following table.
Mirrored memory configurations (both memory boards must be installed with the same configuration):
Memory board
configuration
Bank A
1A and 5A Bank B
2B and 6B Bank C
3C and 7C Bank D
4D and 8D
1 X — — —
2 X X — —
3 X X X —
4 X X X X
After installing FBDIMMs, use RBSU to configure the system for online spare memory support
(" Configuring online spare memory " on page 83 ).
Memory boards and FBDIMMs
The server utilizes two memory boards. Each memory board consists of eight slots, numbered sequentially.
The paired banks are identified by the letters A through D. Each memory board supports 2x1 interleaving.
For maximum performance, HP recommends that both memory boards be populated with the same total
amount of memory to support 4x1 interleaving across both memory branches.
Observe the following warnings when performing a replacement procedure:
WARNING: Always comply with all electrostatic and thermal guidelines to prevent bodily
injury and ensure a properly functioning system when performing hot-plug operations.