Memory mirroring
Memory mirroring offers the strongest memory module 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 memory modules. In the event of an
uncorrectable error, the system switches over to the mirrored copy. This ensures SDDC and multi-bit protection.
The installation guidelines for memory modules are as follows:
●
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
release tabs. This ensures that identical DIMMs are installed in matched pairs—for example, A1 with A2, A3 with A4.
NOTE:
Mirroring and Advanced ECC modes require minimum of two DIMMs per CPU and must be populated in pairs of
either two or four DIMMs per CPU.
Table 33. Processor configuration
Processor
Configuration
Memory population rules
Memory population information
Single CPU
Memory population order
{1,2}, {3,4}
See Memory mirroring note
Sample memory configurations
The following tables show sample memory configurations for one and two processor configurations that follow the appropriate
memory guidelines.
NOTE:
1R and 2R in the following tables indicate single- and dual-rank DIMMs respectively.
Table 34. Memory configurations—single processor
System
Capacity (in
GB)
DIMM Size
(in GB)
Number of
DIMMs
DIMM Rank,
Organization, and
Frequency
DIMM Slot Population
4
4
1
1R, x8, 2400 MT/s,
1R, x8, 2133 MT/s,
1R, x8, 1866 MT/s
A1
8
4
2
1R, x8, 2400 MT/s,
1R, x8, 2133 MT/s,
1R, x8, 1866 MT/s
A1, A2
8
1
1R, x8, 2400 MT/s,
1R, x8, 2133 MT/s,
1R, x8, 1866 MT/s
A1
16
4
4
1R, x8, 2400 MT/s,
1R, x8, 2133 MT/s,
1R, x8, 1866 MT/s
A1, A2, A3, A4
8
2
2R, x8, 2400 MT/s,
2R, x8, 2133 MT/s,
2R, x8, 1866 MT/s
A1, A2
16
1
2R, x8, 2400 MT/s,
2R, x8, 2133 MT/s,
2R, x8, 1866 MT/s
A1
110
Installing and removing system components
