Memory Ras - Hitachi Compute Rack CR 210H User Manual

Memory RAS

This section describes the memory RAS feature supported by the system unit.
Online spare memory
Online spare memory is a function that can be switched online to spare memory
if a correctable memory error (Correctable Error: 1-bit error) occurs frequently.
This provides preventive maintenance of memory switching before an
uncorrectable memory error (Uncorrectable Error: 2-bit error) occurs.
These are the following conditions for using the online spare memory function:
Two or more memory boards should be installed per channel.

8 or 12 memory boards (for 4 channels) per processor.
All memory boards should have the same capacity and same model.

When two processors are installed, the same memory configuration should be

applied to processor 1 and processor 2.
Figure 3-15: The number of the ranks of the memory board
3-20 System Unit Functions
Hitachi Compute Rack 210H User's Guide