HP ProLiant ML570 G4 Server - Manual (Page 44)

Hardware options installation 44
• The system can be configured for any AMP mode in RBSU. RBSU displays a warning message if the
selected AMP mode is not supported by the current configuration. However, if the DIMM
configuration at POST does not meet the requirements for the AMP mode selected in RBSU, the
server defaults to Advanced ECC. The system indicates this by displaying a message during POST
and the status LED for the configured AMP mode flashes amber.
• Unpopulated memory boards (those without any installed DIMMs) can be installed in the server for
storing extra memory boards.
• If the server contains more than 4 GB of memory, consult the OS documentation about accessing the
full amount of installed memory.
Single- and Dual-rank DIMMs
PC2-3200 DIMMs can either be single- or dual-rank. While it is not normally important for you to
differentiate between these two types of DIMMs, certain DIMM configuration requirements are based on
these classifications.
Certain configuration requirements exist with single- and dual-rank DIMMs that allow the architecture to
optimize performance. A dual-rank DIMM is similar to having two separate DIMMs on the same module.
Although only a single DIMM module, a dual-rank DIMM acts as if it were two separate DIMMs. The
primary reason for the existence of dual-rank DIMMs is to provide the largest capacity DIMM given the
current DIMM technology. If the maximum DIMM technology allows for creating 2-GB single-rank DIMMs,
a dual-rank DIMM using the same technology would be 4-GB.
Understanding the existence of single- and dual-rank DIMMs is all that is necessary for understanding the
memory population guidelines of this server.
Advanced ECC Memory
Advanced ECC Memory is the default memory protection mode for this server. In Advanced ECC, the
server is protected against correctable memory errors. The server provides notification if the level of
correctable errors exceeds a pre-defined threshold rate. The server does not fail because of correctable
memory errors. Advanced ECC provides additional protection over Standard ECC in that it is possible to
correct certain memory errors that would otherwise be uncorrectable and result in a server failure.
Whereas Standard ECC can correct single-bit memory errors, Advanced ECC can correct single-bit
memory errors and multi-bit memory errors if all failed bits are on the same DRAM device on the DIMM.
The following guidelines apply to Advanced ECC Memory:
• All general memory requirements apply (" Memory board LEDs and components " on page 17 ).
• Advanced ECC mode is supported with 1, 2, 3, or 4 memory boards.
• Hot-add is always enabled for Advanced ECC.
• Board insertions do not convert the AMP mode while the server is running. A server cannot be
converted from Advanced ECC to Online Spare Memory, mirrored memory, or Hot-Plug RAID
memory by inserting a board while the server is running. Board insertions in Advanced ECC are
solely for making additional memory resources available to the OS.
• Advanced ECC is the only mode in which hot-add operations are supported. This is the only mode in
which the amount of memory available to the OS can be increased without a reboot.
• Hot-add is performed by adding a memory board while the server is running, and the additional
memory is made available to the OS without a reboot. The following rules apply to hot-add
operations:
• Boards must be inserted sequentially.
• Multiple hot-add board insertions can be performed on the same server. For example, if a server
has three empty memory board slots, three hot-add board insertions can be performed.