IBM System x3550 M3 Type 4254 User Manual

Online-spare memory
The memory online-spare feature disables the failed memory from the system
configuration and activates an online-spare DIMM to replace the failed active
DIMM.
You can enable either online-spare memory or memory mirroring in the Setup
utility (see “Using the Setup utility” on page 112). When you use the memory
online-spare feature, consider the following information:
v The memory online-spare feature is supported on server models with an Intel
Xeon
™
5600 series microprocessor.
v When you enable the memory online-spare feature, you must install three
DIMMs per microprocessor at a time. The first DIMM must be in channel 0, the
second DIMM in channel 1, and the third DIMM in channel 2. The DIMMs must
be identical in size, type, rank, and organization, but not in speed. The channels
run at the speed of the slowest DIMM in any of the channels.
v The maximum available memory is reduced to 2/3 of the installed memory
when memory online-spare mode is enabled. For example, if you install 72 GB
of memory using RDIMMs, only 48 GB of addressable memory is available
when you use memory online-spare.
The following table shows the installation sequence for installing DIMMs for each
microprocessor in memory online-spare mode:
Table 13. Memory online-spare mode DIMM population
sequence
Installed
Microprocessor DIMM connector
Microprocessor 1 3, 6, 9
3, 6, 9, 2, 5, 8
3, 6, 9, 2, 5, 8, 1, 4, 7
Microprocessor 2 12, 15, 18,
12, 15, 18, 11, 14, 17,
12, 15, 18, 11, 14, 17, 10, 13, 16
Installing a DIMM
Use this information to install a DIMM.
About this task
To install a DIMM, complete the following steps:
Procedure
1. Read the safety information that begins on “Safety” on page v and “Installation
guidelines” on page 43.
2. Turn off the server and peripheral devices and disconnect the power cords and
all external cables, if necessary.
3. Remove the cover (see “Removing the cover” on page 51).
4. Open the retaining clip on each end of the DIMM connector.
60 IBM System x3550 M3 Type 4254 and 7944: Installation and User's Guide

IBM System x3550 M3 Type 4254 Specifications

General

Brand	IBM
Model	System x3550 M3 Type 4254
Category	Server
Language	English