Because GCM is a client/server application, it is slower to
respond to commands and configuration events than its native counterpart,
the Galaxy Configuration Utility (GCU). While a Galaxy CPU assignment
takes only a few milliseconds and is reflected immediately by the
GCU, the GCM may take several seconds to update its display. For
real-time response, run the GCU (and possibly multiple instances
of the GCU if you have multiple hard partitions).
PC systems running Microsoft Windows require substantially
more physical memory than may be present in a typical desktop PC.
For best performance, your PC should have at least 128 MB (and preferably
more). Disk space is seldom a concern.
The native OpenVMS GCM client does not perform quite as well
as the Windows GCM client. On OpenVMS, user accounts must have substantial
pagefile quota to run the GCM client. HP suggests that you set the PGFLQUO
parameter to 350000 or more. (This is true of all Java applications
on OpenVMS.)
Performance of GCM servers is typically a function of network
behavior. GCM servers sit idle the majority of time, waking up every
so often to issue a heartbeat transaction to other GCM servers or
clients. The GCM server responds to configuration change events
by reencoding the AlphaServer Configuration Tree structure in memory
and then transmitting an XML- encoded representation to all active
GCM servers and clients. This typically creates a burst of approximately
100 KB of network traffic. In an association that contains multiple
GCM servers, with each server actively supporting GCM clients, the
GCM servers must merge these bursts of data into a single configuration
model, and then forward that model to each GCM client. The new model
can require a megabyte or more.
To ensure optimal GCM performance, remember the following:
Large configuration changes usually
occur when GCM servers join or leave the association. Simple command
processing produces far less traffic.
The best way to ensure good GCM server performance
is to limit the number of GCM servers in your association.
You can define multiple associations to keep the
size of any one association from growing excessively large.