Memory Options; Memory Configurations - HP ProLiant DL580 User Manual

Memory options

Memory configurations

To enhance server availability, the server provides the following AMP modes.
Performance mode - Advanced ECC mode default
The default memory mode for the DL580 Gen9 server is Performance mode - Advanced ECC. Performance
mode enables memory bandwidth 2x the DIMM clock speed. Advanced ECC memory can correct single-bit
memory errors and multi-bit memory errors on a single x8 or two adjacent x4 DRAM devices. The DL580
Gen9 server provides notification when correctable errors exceed a predefined threshold. When Advanced
ECC detects uncorrectable errors, the server notifies the user and shuts down the operating system.
Advanced ECC is available for maximum memory configurations.
Lockstep mode - DDDC
The DL580 Gen9 server offers double device data correction (DDDC) with the Intel Xeon Processor E7 series
in Lockstep mode. Memory Bandwidth is reduced to equal clock speed of DIMMs. DDDC produces
significantly less system downtime over Advanced ECC. It can tolerate soft and hard errors encountered in up
to two x4 DRAM devices within any DIMM pair. Tolerating memory faults greatly extends system up-time.
Online spare memory
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.
Mirrored Memory
Errors that are not corrected by ECC or SDDC cannot be corrected by Online Spare memory. Mirrored
Memory provides the greatest protection against memory failure beyond ECC, SDDC, and Online Spare
memory by providing added redundancy in the memory sub-system. Upon detecting an uncorrectable
memory error from a DIMM in a memory cartridge, the processor avoids a system crash by reading the
mirrored DIMM. In this case, the system management routine disables the failed DIMM. Further memory
reads and writes will only occur on the mirrored DIMM.
Limitations to Mirrored Memory mode are as follows:
•
In Mirrored Memory mode, half of the memory is allocated to memory protection.
•
The available memory bandwidth is reduced by up to 50% in this mode.
•
Mirrored Memory, Online Spare mode cannot be enabled simultaneously.
Advanced Memory Protection options are configured in BIOS/Platform Configuration (RBSU) in UEFI System
Utilities. From the System Utilities screen, select System Configuration > BIOS/Platform Configuration
(RBSU)/System Options/Advanced Memory Protection. If the requested AMP mode is not supported by the
installed DIMM configuration, the server boots in Advanced ECC mode.
For more information on the HP UEFI System Utilities, see the HP UEFI System Utilities User Guide on the HP
website (http://www.hp.com/go/ProLiantUEFI/docs).
Hardware options installation 51