HP ProLiant ML350p Gen8 Server - Manual (Page 64)

Hardware options installation 64
is degrading. This allows DIMMs that have a higher probability of receiving an uncorrectable memory
error (which would result in system downtime) to be removed from operation.
Advanced Memory Protection options are configured in RBSU. If the requested AMP mode is not supported
by the installed DIMM configuration, the server boots in Advanced ECC mode. For more information, see
"HP ROM-Based Setup Utility (on page 115 )."
The server also can operate in independent channel mode or combined channel mode (lockstep). When
running in lockstep mode, you gain reliability in one of two ways:
• If running with UDIMMs (built with x8 DRAM devices), the system can survive a complete DRAM failure
(SDDC). In independent channel mode, this failure would be an uncorrectable error.
• If running with RDIMM (built with x4 DRAM devices), the system can survive the complete failure of two
DRAM devices (DDDC). Running in independent mode, the server can only survive the complete failure
of a single DRAM device (SDDC).
Maximum capacity
DIMM type DIMM rank One processor Two processors
RDIMM Single-rank 96 GB 192 GB
RDIMM Dual-rank 192 GB 384 GB
LRDIMM Quad-rank 384 GB 768 GB
UDIMM Single-rank 16 GB 32 GB
UDIMM
Dual-rank 64 GB 128 GB
For the latest memory configuration information, see the QuickSpecs on the HP website
(
http://www.hp.com ).
Advanced ECC
Advanced ECC memory is the default memory protection mode for the server. Standard ECC can correct
single-bit memory errors and detect multibit memory errors. When multibit errors are detected using Standard
ECC, the error is signaled to the server and causes the server to halt.
Advanced ECC protects the server against some multibit memory errors. Advanced ECC can correct both
single-bit memory errors and 4-bit memory errors if all failed bits are on the same DRAM device on the DIMM.
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.