23
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For efficient use of storage, use SATA M.2 SSD modules that have the same capacity to build a
RAID. If the SATA M.2 SSD modules have different capacities, the lowest capacity is used
across all SATA M.2 SSD modules in the RAID.
SATA M.2 SSD adapter module
The SATA M.2 SSD adapter module supports hot swapping.
DIMMs
This section introduces the basic concept of DIMM, DIMM mode and DIMM installation guidelines.
About DIMMs
DIMMs include DDR4 and PMem 200 DIMMs. DDR4 DIMMs include LRDIMM and RDIMM.
1.
DDR4 and PMem 200
•
DDR4 is the most common type of DIMM. The data in DDR4 will be lost in the event of an
unexpected power failure of the server system.
•
PMem 200 has the following two features:
Compared with DDR4, PMem 200 has a larger capacity for a single memory module.
PMem 200 (such as Barlow Pass) has data protection in case of power failure. Data in
PMem 200 will not be lost in the event of unexpected power failure of the server system.
2.
RDIMM and LRDIMM
•
RDIMM provides address parity protection.
•
LRDIMM provides a larger capacity and bandwidth for the system.
3.
Rank
The number of ranks is usually 1, 2, 4, or 8, generally abbreviated as 1R/SR, 2R, 4R, 8R, or
single-rank, dual-rank, quad-rank, or 8-rank.
•
A 1R DIMM has a set of DIMM chips that will be accessed when data is written to or read from
the DIMM.
•
A 2R DIMM is equivalent to a module containing two 1R DIMMs, but only one rank can be
accessed at a time.
•
A 4R DIMM is equivalent to a module containing two 2R DIMMs, but only one rank can be
accessed at a time.
•
A 8R DIMM is equivalent to a module containing two 4R DIMMs, but only one rank can be
accessed at a time.
When writing or reading data in a DIMM, the server memory control subsystem will select the correct
rank from the DIMM.
4.
DIMM specifications
