Dell PowerEdge M420 Dell PowerEdge M620 Systems Owner's Manual - Page 33
Memory Optimized (Independent Channel) Mode, Memory Sparing, Memory Mirroring - dimm slots
View all Dell PowerEdge M420 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 33 highlights
Memory Optimized (Independent Channel) Mode This mode supports SDDC only for memory modules that use x4 device width and does not impose any specific slot population requirements. Memory Sparing NOTE: To use memory sparing, this feature must be enabled in the System Setup. In this mode, one rank per channel is reserved as a spare. If persistent correctable errors are detected on a rank, the data from this rank is copied to the spare rank and the failed rank is disabled. With memory sparing enabled, the system memory available to the operating system is reduced by one rank per channel. For example, in a dual-processor configuration with sixteen 4 GB dual-rank DIMMs, the available system memory is: 3/4 (ranks/channel) × 16 (DIMMs) × 4 GB = 48 GB, and not 16 (DIMMs) × 4 GB = 64 GB. NOTE: Memory sparing does not offer protection against a multi-bit uncorrectable error. NOTE: Both Advanced ECC/Lockstep and Optimizer modes support Memory Sparing. Memory Mirroring Memory Mirroring offers the strongest DIMM reliability mode compared to all other modes, providing improved uncorrectable multi-bit failure protection. In a mirrored configuration, the total available system memory is one half of the total installed physical memory. Half of the installed memory is used to mirror the active DIMMs. In the event of an uncorrectable error, the system will switch over to the mirrored copy. This ensures SDDC and multi-bit protection. Memory installation guidelines: • Memory modules must be identical in size, speed, and technology. • DIMMs installed in memory sockets with white release tabs must be identical and similar rule applies for sockets with black and green release tabs. This ensures that identical DIMMs are installed in matched pairs for example, A1 with A2, A3 with A4, A5 with A6, and so on. Sample Memory Configurations The following tables show sample memory configurations that follow the appropriate memory guidelines stated in this section. NOTE: 16 GB quad-rank RDIMMs are not supported. NOTE: 1R and 2R in the following tables indicate single- and dual-rank DIMMs. Table 1. Memory Configurations - Single Processor System Capacity (in GB) 2 DIMM Size (in GB) 2 Number of DIMMs 1 4 2 2 8 2 4 12 2 6 Organization and Speed 1R x8, 1333 MT/s 1R x8, 1600 MT/s 1R x8, 1333 MT/s 1R x8, 1600 MT/s 1R x8, 1333 MT/s 1R x8, 1600 MT/s 1R x8, 1333 MT/s 1R x8, 1600 MT/s DIMM Slot Population A1 A1, A3 A1, A2, A3, A4 A1, A2, A3, A4, A5, A6 33