This chapter is intended for customers migrating from earlier releases of PE to PE Version 2.4. It contains specific information on some differences between earlier releases that you need to consider prior to installing or using PE Version 2.4. To find out which release of PE you currently have installed, use lslpp.
If you have an earlier release of PE already installed, installing PE Version 2.4 filesets involves a migration installation on top of the earlier filesets. The earlier filesets will be replaced, unnecessary files and directories will be removed and rendered obsolete, and disk space conserved.
There are several files saved as part of the migration installation, in case those files were previously modified. For specific details, refer to "How Installing the poe Fileset Alters Your System".
To the ODM and lslpp, however, the earlier filesets will show as installed but marked "OBSOLETE". Additionally, some older directories and installation-related files may remain. A potential problem that may result from this is that if you later attempt to remove an older fileset, files from the newer fileset may be removed instead.
To avoid this potential side effect, completely remove older releases of the PE filesets before you begin installation. For more details, see "Migration Installation".
PE Version 2.4 commands and applications are compatible with AIX Version 4.3.2 or later only, not with earlier versions of AIX.
PE on the SP requires that all nodes involved in a parallel job be running the same level of PE.
When LoadLeveler and PE coexist on a node, they must be at one of these levels:
The PE libraries used to run a job on a node must be compatible with the PSSP libraries on that node. The following combinations are compatible:
The restrictions are the same in all cases:
PE does not support node-by-node migration. All of the nodes in a system partition must be migrated to a new level of PE at the same time. PE supports running a particular release of PE on plus or minus one level of AIX or PSSP, which lets customers migrate to a new level of AIX or PSSP without having to change to a new level of PE.
In general, the preferred upgrade path for PE is to upgrade the AIX level, then the PSSP level, and then the PE level. There are a number of migration paths available:
For example, a customer running PE 2.3, PSSP 2.3, and AIX 4.2.1 will be able to migrate to AIX 4.3.2 without migrating to a new level of PE (or PSSP).
|Note:||A PTF is required for PE 2.3 to run in binary compatibility mode on AIX 4.3.2, but the PTF can be applied to PE 2.3 before migrating from AIX 4.2.1 to 4.3.2.|
Table 3. PE, PSSP, and AIX Versions for a Workstation Cluster or Partition
|Version of PE Installed on Workstation Cluster or Partition||Required Version of PSSP||Required Version of AIX|
|2.4||3.1||4.3.2 or later|
|2.3||2.3 or 2.4||4.2.1 or 4.3.1|
The Parallel Client Function feature available in Version 1 is no longer available or supported in Version 2. You need to install the entire POE fileset on any IBM RS/6000 workstation running parallel jobs.
The Parallel Desktop function of PE Version 1 has been removed. It is no longer supported.
POE no longer uses its own compiler configuration file (/usr/lpp/ppe.poe/lib/poe.cfg is no longer shipped). If you had modified poe.cfg in previous versions, you may need to make similar changes in the default compiler configuration files or to your compiler scripts. The poe.cfg file is saved as part of a migration installation, so any previous changes are preserved. See "How Installing the poe Fileset Alters Your System" for the files that are saved.
Use of the SP_NAME environment variable, which determines the job management system to use (LoadLeveler or the SP system Resource Manager), is changed for this release. If all nodes to be used for the parallel job exist in a PSSP 2.4 partition, the SP_NAME environment variable should be set to the name of the control workstation of the SP system on which these nodes exist. This is the only case that results in POE contacting the Resource Manager rather than LoadLeveler for node allocation requests. See "When to Install ssp.clients (SP Resource Manager)" for more information.