Administering Platform LSF - SAS

Changing Default LIM Behavior to Improve
Performance
Chapter 37
Tuning the Cluster
You may want to change the default LIM behavior in the following cases:
◆ In very large sites. As the size of the cluster becomes large (500 hosts or
more), reconfiguration of the cluster causes each LIM to re-read the
configuration files. This can take quite some time.
◆ In sites where each host in the cluster cannot share a common
configuration directory or exact replica.
In this section ◆ “Default LIM behavior” on page 487
◆ “Change default LIM behavior” on page 487
◆ “Reconfiguration and LSF_MASTER_LIST” on page 488
◆ “How LSF works with LSF_MASTER_LIST” on page 488
◆ “Considerations” on page 489
Default LIM behavior
By default, each LIM running in an LSF cluster must read the configuration files
lsf.shared and lsf.cluster.cluster_name to obtain information about
resource definitions, host types, host thresholds, etc. This includes master and
slave LIMs.
This requires that each host in the cluster share a common configuration
directory or an exact replica of the directory.
Change default LIM behavior
The parameter LSF_MASTER_LIST in lsf.conf allows you to identify for the
LSF system which hosts can become masters. Hosts not listed in
LSF_MASTER_LIST will be considered as slave-only hosts and will never be
considered to become master.
By setting this parameter, you can reduce the time it takes to reconfigure a
cluster and requests made to the file server. Only hosts listed in
LSF_MASTER_LIST will read lsf.shared and lsf.cluster.cluster_name.
Configuration information will then be propagated from the master LIM to
slave-only LIMs.
Setting LSF_MASTER_LIST (lsf.conf)
1 Edit lsf.conf and set the parameter LSF_MASTER_LIST to indicate hosts
that are candidates to become the master host. For example:
LSF_MASTER_LIST="hostA hostB hostC"
The order in which you specify hosts in LSF_MASTER_LIST is the preferred
order for selecting hosts to become the master LIM.
2 Save your changes.
3 Reconfigure the cluster with the commands lsadmin reconfig and
badmin mbdrestart.
Administering Platform LSF 487