Hardware options installation 50
Advanced ECC provides additional protection over Standard ECC because it is possible to correct certain
memory errors that would otherwise be uncorrected and result in a server failure. Using HP Advanced
Memory Error Detection technology, the server provides notification when a DIMM is degrading and has a
higher probability of uncorrectable memory error.
Online Spare memory configuration
Online spare memory provides protection against degraded DIMMs by reducing the likelihood of
uncorrected memory errors. This protection is available without any operating system support.
Online spare memory protection dedicates one rank of each memory channel for use as spare memory. The
remaining ranks are available for OS and application use. If correctable memory errors occur at a rate
higher than a specific threshold on any of the non-spare ranks, the server automatically copies the memory
contents of the degraded rank to the online spare rank. The server then deactivates the failing rank and
automatically switches over to the online spare rank.
Lockstep memory configuration
Lockstep mode provides protection against multi-bit memory errors that occur on the same DRAM device.
Lockstep mode can correct any single DRAM device failure on x4 and x8 DIMM types. The DIMMs in each
channel must have identical HP part numbers.
Advanced ECC population guidelines
For Advanced ECC mode configurations, observe the following guidelines:
•
Observe the general DIMM slot population guidelines.
•
DIMMs may be installed individually.
Online spare population
For Online Spare memory mode configurations, observe the following guidelines:
•
Observe the general DIMM slot population guidelines.
•
Each channel must have a valid online spare configuration.
•
Each channel can have a different valid online spare configuration.
•
Each populated channel must have a spare rank:
o
A single dual-rank DIMM is not a valid configuration.
o
LRDIMMs are treated as dual-rank DIMMs.
Lockstep Memory population guidelines
For Lockstep memory mode configurations, observe the following guidelines:
•
Observe the general DIMM slot population guidelines.
•
DIMM configuration on all channels of a processor must be identical.
•
In multi-processor configurations, each processor must have a valid Lockstep Memory configuration.