IBM RS/6000 SP Problem Determination Manual page 154

performance across the switch is of great importance. By partitioning the
system, the nodes may have to be concentrated on the switches, therefore
reducing bandwidth.
5.2.5 Configuration Files
All the switch configuration files at PSSP 2.1 are in the following directory:
/spdata/sys1/syspar_configs
The system size directories are below this directory based on the number of
switch boards in the system (or frames, if there is no switch). For example:
/spdata/sys1/syspar_configs/1nsb0isb
Beneath these directories are the config directories which determine how many
partitions will be in the system and how many nodes will be in each one. For
example:
/spdata/sys1/syspar_configs/1nsb0isb/config.8_8
Beneath this are the layout directories which determine which nodes will go into
which partition. For example:
/spdata/sys1/syspar_configs/1nsb0isb/config.8_8/layout.1
There is a file in this directory called layout.desc that describes the actual layout
in terms of which node goes in which partition. Beneath this are the syspar
directories, one for each partition that has been selected from the config
directory. For example:
/spdata/sys1/syspar_configs/1nsb0isb/config.8_8/layout.1/syspar.1
/spdata/sys1/syspar_configs/1nsb0isb/config.8_8/layout.1/syspar.2
Within these directories there are three files: topology, nodelist and custom.
Actually, of these four files (these three plus the layout.desc), only the custom
file is a real file; all the others are symbolic links to files in the following
directories:
/spdata/sys1/syspar_configs/topologies
/spdata/sys1/syspar_configs/descriptions
/spdata/sys1/syspar_configs/nodelists
The topology file we have already discussed earlier in the chapter. The nodelist
file is similar to the layout.desc file, except that it has been split out into its
respective partition and contains only a list of its own nodes.
The custom file is the only one that gets modified. The others are selected as
supplied to match the requirements of your partitioning. The custom file gets
updated during the apply of the configuration, and this will be covered later in
more detail. It will contain information about the version of POWERparallel
System Support Programs in the partition, for example.
The diagram in Figure 62 on page 135 is intended to assist in the understanding
of the directory structure, although you only really need to use this information if
you need to debug problems with System Partitioning or the switch. All the
configurations can be done from the SMIT panels without this knowledge.
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