Advanced memory protection for HP ProLiant 300 series G4 servers

• Memory will automatically be tested in POST whenever the memory configuration has changed (see

“Configuring AMP,” below).

• RBSU will now allow the system to be configured for Online Spare, even when the DIMM

configuration is invalid (see “Configuring AMP,” below).

• Correctable threshold errors are still monitored after an Online Spare switchover. On the previous

generation (G3) systems, after an Online Spare switchover had occurred, the next time any DIMM

exceeded its correctable threshold, it would be detected and reported. After that, though, if any

more DIMMs exceeded their correctable threshold on a G3 system, this would not be detected by

the system and would not be reported (see “Managing Failures in a system with online spare

enabled,” below). G4 systems will continue to monitor correctable threshold errors until all banks of

memory have exceeded the correctable error threshold.

• Symmetric Memory Mode feature added (See “Symmetric Memory” section).

• Background Scrubbing feature added (See “What is scrubbing?” section).

• The Online Spare Bank is periodically tested during normal system operation. If an uncorrectable

error is detected in the Online Spare Bank prior to an Online Spare switchover, the system will

continue to operate normally, but the system will not switch to the Online Spare Bank if a DIMM

exceeds the correctable error threshold. This prevents the system from switching over to memory that

would result in an uncorrectable memory error and subsequent crash.

There is no additional software required to enable AMP features. Previous generations (G2) required

the system management (health) driver to be loaded. The health driver is not required in 300 series

G4 servers but is required to provide console messaging and messaging with System Insight

Manager.

Dual rank vs. single rank DIMMs

DIMMs can be classified as single- or dual-rank. Single rank and dual rank DIMMs (also known as

single and double-sided DIMMs) may be the same capacity, but are not equivalent in all cases. For

instance, many ProLiant servers require installing DIMMs in pairs. In this instance, a 1 GB single-rank

DIMM is not equivalent to a 1 GB dual-rank DIMM. Also, single- and dual-rank DIMMs of the same

capacity may not be equivalent for certain population rules in AMP modes. On some ProLiant

products, combinations of these will work and on other products they may not. There may also be

certain configuration rules to allow combinations of single and dual-rank DIMMs to operate together.

Refer to the product QuickSpecs for specific details on what DIMMs are supported on your server.

Configuration rules for online spare

The configuration rules for Online Spare are very simple. If these rules are not followed and the

system is configured for Online Spare mode, the system will automatically boot into Advanced ECC

mode. On each reboot, the system will attempt to enter Online Spare mode as long as the system is

configured for Online Spare mode. A warning message will be displayed at POST and logged to the

Integrated Management Log (IML). When the user configures the system for Online Spare mode, the

system will remain configured for this mode even if the system boots in Advanced ECC mode.

The general configuration rules for Advanced Memory Protection are:

• The banks are designated A, B, C, and D.

• Memory must be populated sequentially, starting with bank A.

• DIMMs must be the same capacity and have the same number of ranks within a bank.

• On systems that support DDRII memory, dual-rank DIMMs are not supported.