OSF DCE Administration Guide--Core Components

Chapter 13. How CDS Looks Up Names
This chapter illustrates the relationship between a name and the physical resource that it
describes, and explains how CDS handles requests to look up names. Understanding
these concepts can help you to plan for the location of clearinghouses and directories in
your cell namespace. It can also help you to isolate the source of a problem if you
encounter lookup errors or failures. Note that the figures in this chapter do not reflect the
actual structure of a typical DCE cell namespace. For simplicity, the figures show fewer
directories and directory levels.
13.1 Translating from Names to Resources
Just as directory names in a logical namespace hierarchy translate to physical replicas in
clearinghouses, CDS names translate to physical resources that are used either internally
by CDS or by client applications. The attributes of a name are what make the translation
possible. This section describes the relationship between CDS names and the physical
resources that they describe.
Figure 13-1 shows three directories and their contents in a logical namespace, and how
replicas of those directories are physically implemented in two clearinghouses. The
clearinghouses themselves have CDS names: /.:/Paris_CH on Node 1 and /.:/NY_CH on
Node 2. The _CH suffix is a recommended convention for naming clearinghouses. The
/.:/Paris_CH clearinghouse contains replicas of the root directory and the
/.:/subsys/PrintQ directory. The /.:/NY_CH clearinghouse contains replicas of the root
directory and the /.:/subsys directory. Recommended practice is to create at least two
replicas of every directory. Therefore, the /.:/subsys and /.:/subsys/PrintQ directories
each need to be replicated in at least one other clearinghouse somewhere in the cell.
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