HP ProLiant DL980 DL980 G7 Maintenance & Service Guide - Page 47

For the latest memory configuration information, see the QuickSpecs on the HP website (http://www.hp.com/go/ProLiant). Advanced ECC memory population guidelines Advanced ECC memory is the default memory protection mode for the server. Up to 2-TB of active memory using 16-GB DIMMs is supported in this AMP mode. Advanced ECC can correct single-bit and multi-bit memory errors on a single x8 or two adjacent x4 DRAM devices. The server provides notification when correctable error events have exceeded a pre-defined threshold rate. When uncorrectable errors are detected using Advanced ECC, the server notifies the user and shuts down the operating system. Online Spare memory population guidelines Online spare memory provides protection against persistent DRAM failure. It monitors DIMMs for excessive correctable errors and copies the content of an unhealthy rank to an available spare rank in advance of multi-bit or persistent single-bit failures that may result in uncorrectable faults. Rank-sparing is more efficient than DIMM-sparing since only a portion of a DIMM is set aside for memory protection. When Online Spare memory is enabled, the first ranks of DIMM pair, 1A/8A, are set aside as the sparing ranks. Therefore, the available memory is reduced by the size of the first ranks of DIMM pair 1A/8A. If a DIMM rank on either of the SMI buses exceeds its correctable ECC threshold, then the contents of the failing DIMM ranks are copied to the spare DIMM ranks. Once the copy is complete, all memory accesses to the previous failing DIMM ranks go to the spare DIMM ranks. No performance penalty occurs for rank-sparing, other than the time it takes to copy the data from the failing rank to the spare rank upon an error condition. The following population rules apply to each memory cartridge. Begin with the DIMM installation guidelines (on page 43) with these additional constraints: • All installed processors must contain a valid sparing configuration. • If installing mixed rank DIMMs in a cartridge, follow the mixed rank installation rules of the DIMM installation guidelines (on page 43). • Rank sparing requires that the spare ranks of the DIMM pair 1A/8A be at least as large as any other DIMM rank on the DDR3 channels of the cartridge. To determine the size of a single rank in a DIMM, divide the total DIMM size by the number of ranks. For example, the rank size of a dual-rank 2-GB DIMM is 1 GB and the rank size of a dual-rank 4-GB DIMM is 2 GB. Therefore, it is possible to support rank sparing with mixed DIMM pair sizes in the cartridge if the 1A/8A pair is populated with the 4-GB DIMMs and the other pairs are populated with either the identical 4-GB or 2-GB DIMMs (pairs C and D are not required to be populated). In this case, the 2-GB rank size of the 4-GB DIMMs in the 1A/8A pair is equal to or greater than the rank size of the other installed DIMMs. However, the server cannot support DIMM sparing in this example if the 2-GB DIMMs are populated in the 1A/8A pair locations and the 4-GB DIMMs are populated in any of the remaining DIMM pair locations. This is because it violates the rule requiring that the spare rank size of DIMM pair 1A/8A (1 GB) be equal to or larger than the single rank size of the other DIMM pair locations, since the Illustrated parts catalog 47