Advanced memory protection for HP ProLiant 300 series G4 servers

which exceeded the correctable threshold and was deactivated cannot result in an uncorrectable error

once the online spare switchover is complete.

Benefits of online spare memory

With Online Spare Memory, degraded memory is automatically disengaged and a fresh set of

memory is used in its place. This brings the reliability of the system to the pre-failure level without any

service interruption and without compromising system availability.

This solution is beneficial to businesses that do not have a permanent IT staff, do not have

replacement memory on hand, or cannot bring down the server for any reason until a scheduled

downtime. If a memory module has achieved its pre-defined threshold of correctable memory errors,

its chance of encountering uncorrectable errors increases dramatically. Online Spare allows the

system to automatically deactivate memory that is at a high risk of receiving an uncorrectable error,

and replace it with good memory. No interruption to system operation occurs. An uncorrectable error

would result in a system crash and unscheduled downtime. Thus, Online Spare Mode decreases the

chances of unscheduled downtime and system crashes due to uncorrectable memory errors.

Online Spare Memory is a higher level of memory protection that complements Advanced ECC

support. Online Spare Memory is a user selectable option. Users can choose to disable Online Spare

and make all installed memory available to the operating system and applications, or they can

choose to enable Online Spare and reduce the amount of memory available to the OS and

applications in return for a higher level of protection against uncorrectable memory errors. By default,

Online Spare Mode is disabled.

Deployment considerations

There are a few key factors to consider when determining what level of AMP support should be

enabled:

• What features are supported on the ProLiant server being deployed?

• What level of protection is desired?

• What the cost of implementation is for the AMP mode?

To determine what AMP features are supported on your ProLiant server, refer to the Product

QuickSpecs. The above sections detail the various protection modes and the benefits of each. The

cost of implementation for Online Spare over Advanced ECC is the hardware cost of the extra DIMMs

required for the spare bank. If Standard ECC or Advanced ECC is implemented, there is no cost

associated with extra hardware.

Implementation differences between ProLiant 300 series G3

and G4 servers

The implementation of AMP support for G4 300-series ProLiant servers is very similar to the

implementation on G3 servers with the following exceptions:

• The configuration rules have changes in regards to dual-ranked DIMMs (see “Configuration rules,”

below).