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In 'uptime' output, what does "load average" mean, and when does the number become "bad"?

Xitron
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Last Modified: 2011-10-03
According to the AIX man page for the 'uptime' command, the following is true:

"The uptime command prints the current time, the length of time the system has been up, the number of users online, and the load average. The load average is the number of runnable processes over the preceding 5-, 10-, 15-minute intervals."

My numbers are usually below one, so I haven't been concerned.  Lately, the numbers are sometimes getting higher.

Can you tell me what the "load average" or "runnable processes" means, and at what point the number becomes "bad"?

In other words, is 1.5 okay, but 5.3 bad?  The man page is not very informative on this issue.

Thank you!!

Unca Xitron
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Commented:
Depends on how you tune system (task scheduler, swap management, disk buffers, mealloc() )
Install and patch bos.adt.samples package from 1st CD, so you get vmtune utiliy to tune malloc parameters, especially swap threshold can be multiple megabytes instead of default one, and read the README as dmesg said, to tune individual applications.
Check out "smitty wlm" , it has very simple interface and helps you group and prioritize applications as necessary ( first try monitoring mode to see how well you grouped your processes )
e.g.
Kernel min=20% max=100% cpu and memory (root is included here, do not lower that 20%)
Interactive logins (gid=users) -"-
Database application (uid=postmaster) -"-
Webserver (program=/usr/IBMHTTPServer/bin/httpd)-"-
default -"-
i.e. you do not know how much resource each one needs, so give them equal share of resources, so they all run at once without bringing others down, then you will gain experience who needs a bit more or less and adjust settings accordingly.
I run 12 workload classes on one test server, this becomes less on actual business servers

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Commented:
My thanks to all for your excellent information!

Unca Xitron
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