HP ProLiant BL680c G5 Server-Blade User Manual
Page 30
Hardware options installation 30
•
FBDIMMs must be installed in sequential order, beginning with bank A.
For Advanced ECC mode, populate the FBDIMM slots as specified in the following table:
Configuration Bank
A
Branch 0
1A, 5A
Bank B
Branch
19B, 13B
Bank C
Branch 0
2C, 6C
Bank D
Branch 1
10D, 14D
Bank E
Branch 0
3E, 7E
Bank F
Branch 1
11F, 15F
Bank G
Branch 0
4G, 8G
Bank H
Branch 1
12H, 16H
1
X — — — — — — —
2
X X — — — — — —
3
X X X — — — — —
4
X X X X — — — —
5
X X X X X — — —
6
X X X X X X — —
7
X X X X X X X —
6
X X X X X X X X
After installing FBDIMMs, use RBSU to verify the that the server blade is configured for Advanced ECC
Configuring Advanced ECC memory
Online spare memory configuration
Online spare memory provides protection against degrading FBDIMMs by reducing the likelihood of
uncorrectable memory errors. This protection is available without any operating system support.
An understanding of single-rank and dual-rank FBDIMMs is required to understand memory usage in
online spare mode. FBDIMMs can either be single-rank or dual-rank. Certain FBDIMM configuration
requirements are based on these classifications. A dual-rank FBDIMM is similar to having two single-rank
FBDIMMs on the same module. Although only a single FBDIMM module, a dual-rank FBDIMM acts as two
separate FBDIMMs. The purpose of dual-rank FBDIMMs is to provide the largest capacity FBDIMM for the
current DRAM technology. If the current DRAM technology allows for 2-GB single-rank FBDIMMs, a dual-
rank FBDIMM using the same technology would be 4-GB.
In online spare mode, a single rank of memory acts as the spare memory. For single-rank FBDIMMs, the
entire FBDIMM acts as the spare memory. For a dual-rank FBDIMM, only half of the FBDIMM acts as the
spare memory while the other half is available for operating system and application usage.
If one of the non-spare FBDIMMs receives correctable memory errors at a higher rate than a specific
threshold, the server blade automatically copies the memory contents of the degraded rank to the online
spare rank. The server blade then deactivates the failing rank and automatically switches over to the
online spare. Because FBDIMMs that experience a high rate of correctable memory errors also have a
higher probability of receiving an uncorrectable memory error, this configuration reduces the likelihood of
uncorrectable memory errors that would result in server blade downtime.
Online spare is performed per branch of the memory controller. For a server blade with both branches
populated, two ranks are used for online spare memory. One branch can fail over to the associated
online spare while the other branch is still protected.
Each branch is made up of four banks:
•
Branch 0 contains banks A, C, E, and G
•
Branch 1 contains banks B, D, F, and H