Ibm Exflash Memory-Channel Storage - IBM System x3950 X6 Product Manual

The following memory protection technologies are supported:
ECC

Chipkill (for x4-based memory DIMMs)

Redundant bit steering (Double Device Data Correction)

Memory mirroring

Memory rank sparing

Chipkill and Redundant Bit Steering are supported in RAS mode. Chipkill is supported in Performance
mode.
If memory mirroring is used, DIMMs must be installed in pairs for Performance mode (minimum of one
pair per each processor) and quads for RAS mode. DIMMs in the pair/quad must be identical in type and
size.
If memory rank sparing is used, then a minimum of two single-rank or dual-rank DIMMs must be installed
per populated channel (the DIMMs do not need being identical). In rank sparing mode, one rank of a
DIMM in each populated channel is reserved as spare memory. The size of a rank varies depending on
the DIMMs that are installed.

IBM eXFlash memory-channel storage

IBM eXFlash memory-channel storage are storage offerings in the physical form of memory DIMMs.
These IBM eXFlash DIMMs are installed in memory DIMM sockets but appear to the operating system
and applications as block storage devices. This new and innovative technology brings storage electrically
closer to the processor subsystem, therefore improving performance considerably.
Note: Both the x3850 X6 and the x3950 X6 support at most 32 eXFlash DIMMs.
The following table shows the supported eXFlash DIMMs.
Table 7. Internal storage expansion options
Part Feature Name and description
number code
00FE000 A4GX IBM eXFlash 200GB DDR3 Storage DIMM
00FE005 A4GY IBM eXFlash 400GB DDR3 Storage DIMM
IBM System x3950 X6
Maximum
supported
x3950 X6
32
32
15