Online Spare Memory
Online spare memory provides a higher level of memory protection than Advanced ECC. With online spare memory, the probability of a server failing because of uncorrectable memory errors is reduced.
In this mode, degraded memory that is receiving a high rate of correctable memory errors is automatically disengaged and a replacement set of memory is used in its place. Because DIMMs that are receiving a high rate of correctable memory errors have an increased probability of receiving an uncorrectable memory error (which results in a server failure), the server experiences higher availability. The degraded memory can be replaced during scheduled downtime and poses no additional risk to the server.