Improving client host performance

This chapter presents techniques for improving Rational® ClearCase® performance on the client host. Administrative responsibilities related to client host performance include the following:

Establishing standards for client host configurations (memory, processing power, network interface characteristics, and local storage).
Understanding MVFS cache sizes and how to adjust them.
Understanding view caches and how to adjust them.
Establishing sitewide defaults for cache sizes.

Note: Most client host performance tuning procedures deal with the MVFS. They do not apply to Rational ClearCase clients that run only snapshot or Web views.

Client host configuration guidelines

Rational ClearCase client software makes demands on host memory, CPU, and storage subsystems that are comparable to the demands made by similar workstation applications. Any computer configured to support such applications will deliver good performance on the majority of Rational ClearCase client tasks.

Because Rational ClearCase is a distributed application, it also requires good performance from the client host's network interface and the network to which it is connected. Poor network performance has a negative impact on the responsiveness of even a well-configured Rational ClearCase client host.

Additional memory might be appropriate for some client hosts. For example, a client host that is expected to do additional work, such as hosting distributed builds or shared views, needs additional memory and perhaps a larger, higher-performance disk subsystem. And any client that must run other workstation applications while it is also running Rational ClearCase might need to have its resources adjusted to adequately support simultaneous use of both.

Examining and adjusting MVFS cache size
Rational ClearCase hosts that use dynamic views can benefit from MVFS cache tuning. Default MVFS cache sizes scale automatically based on host memory and are appropriate for a wide range of client needs, but you might want to change default MVFS cache sizes to improve performance in specific cases.
View caches
To improve its performance, the view_server process associated with a view maintains a cache. The default size of this cache is adequate for typical views, but a larger cache can further improve the performance of views in which very large software systems are built by omake or clearmake.
Reference information
The mvfsstat and mvfscache utilities are intended primarily to help IBM Software Support for Rational products diagnose problems with the MVFS. No locks or mastership restrictions apply for either of these utilities, but certain options require privileged user status.

Parent topic: Administering Rational ClearCase