"Load Balancing": How Busy are the servers?

[Marc G. Fournier]

Two part question here ... first leads into the second, and the second 
might answer the first ...

1. What variables on a server should be monitored to determine how busy a 
server is?  For instance, I've always been taugth that 'loadavg' is not an 
indication of how busy a server is, since a high loadavg on a single CPU 
server might be an overloaded server, but moderately loaded on a dual CPU 
server ... disk i/o, cpu usage, ethernet throughput ... what else?

2. Are there any tools that I can run to give me a point in time "summary" 
of how busy a server is based on these several factors?

Basically, I'd like to keep track of multiple servers and be able to say 
"this server is running >75% of capacity, time to upgrade or move things 
off of it" ... if its possible ... ?

thanks ...

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Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy at hub.org           Yahoo!: yscrappy              ICQ: 7615664