Chapter 6: Tru64 UNIX Cluster Hooks - File System Hierarchy, CDSL, PID

Overview

In this chapter we will begin the discussion of the various components included in the base Tru64 UNIX operating system that enable a more seamless transition from a standalone system to a cluster.

We will cover the following components:

	Section
The Context Dependent Symbolic Link (CDSL)	6.1.1, 6.4
Changes to the Runtime Configuration	6.1.2
The File System Hierarchy	6.2
Expanded Process IDs	6.5

The first and most significant change that was made to Tru64 UNIX was to have a transparent method for the operating system to locate its configuration information, executables, layered applications, etc., as well as to structure the basic file system hierarchy in such a way that it would not matter whether the system is standalone or in a cluster.

The method adopted is to split information into member-specific and cluster-common files for all Tru64 UNIX systems, whether they are in a cluster or standalone configuration. The cluster-common files are located in the files' normal location, while the member-specific files are located somewhere new (but appear to be located in the files' normal location – more on this in the following sections). The member-specific files are actually located in one of three primary locations:

• /cluster/members/membern

• /usr/cluster/members/membern

• /var/cluster/members/membern

(Where "n" is a number between 0 and 63 inclusive.)

Note

The member0 directories are primarily used as a standalone system's member-specific directories. While technically it is unnecessary for a standalone system to have member-specific directories (since it is not a member of anything except your computer room), it keeps the layout consistent between standalone and clustered environments. In a cluster, it is used as a repository for generic versions of member-specific files. Cluster member IDs range from 1 to 63.