Planning and Configuring HP DCE 1.7

Planning and Conﬁguring HP DCE 1.7 3-7

Before Installing HP DCE/9000 Version 1.7

Preinstallation Planning

Cell Directory Service Conﬁguration

In conﬁguring CDS servers and clients, pay careful attention to the HP

DCE/ 9000 hardware requirements for the DCE product. (See “Hardware

and Software Requirements” in this chapter.) Appropriate kernel

conﬁguration, memory, disk, and especially swap space are essential to

the proper functioning of the CDS subsystem.

Tape backups of the CDS server database are extremely important for

recovery from catastrophic problems. HP strongly recommends regular

tape back ups of all CDS server databases, especially those containing

any master replicas. Tape backups and restorations require the CDS

server in question to be temporarily shut down.

Most CDS problems, however, do not require resorting to tape backup.

Directory replication provides continuous online backup for most

failures, with faster recovery and less stale data. This makes directory

replication highly desirable for all DCE cells. Every cell should conﬁgure

at least two CDS servers, and read-only replicas of all directories should

be created on the backup server. In this conﬁguration, backup is

continuous, and recovery only involves switching the role of the servers.

Multiple CDS servers can be conﬁgured for speciﬁc purposes in the cell.

Multiple CDS servers with read-only replicas of all directories in the

name space should always be present for backup and recovery purposes.

Performance considerations may also make the conﬁguration of other

CDS servers desirable. For instance, administrators of very busy cells or

cells with large numbers of nodes should consider adding additional CDS

servers to share the name space processing load. Similarly,

administrators of cells with groups of nodes separated by WAN links

should consider providing a local CDS server for each group to enhance

performance. Administrators with very large cells may want to partition

the name space among several CDS servers, replicating only the locally

used directories, to distribute the storage overhead of the name space.

Each of these CDS conﬁguration strategies is documented in the

OSF DCE Administration Guide — Core Services.

Time Services

A minimum of three DTS servers is recommended for any cell with three

or more member systems. If you use an external time provider, you can

have only one of these running in a cell.