Revision as of 16:38, 29 December 2006

What do the CPU statistics mean - is this the load average?

No. Unfortunately, the original definition of the various CPU statistics was a little vague. It referred to a "percentage", without specifying what period this should be calculated over. It was therefore implemented slightly differently on different architectures.

The 5.4 release has clarified the situation, and standardised on calculating these percentages over a minute. The relevant MIB descriptions have been updated to make the desired behaviour more explicit.

The Net-SNMP agent also includes "raw counters", which can be used to calculate the percentage usage over any desired period. This is the "right" way to handle things in the SNMP model. The original percentage objects have been deprecated, and may possibly be removed in a future release of the agent.

Note that this is different from the Unix load average, which is available via the loadTable, and is supported on all architectures.

   FAQ:Agent
   

1. What MIBs are supported?
2. What protocols are supported?
3. How do I configure the agent?
4. How do I remove a MIB from the agent?
5. I've installed a new MIB file. Why can't I query it?
6. How do I add a MIB to the agent?
7. What's the difference between 'exec', 'sh', 'extend' and 'pass'?
8. What's the difference between AgentX, SMUX and proxied SNMP?
9. What is the purpose of 'dlmod'?
10. Which extension mechanism should I use?
11. Can I use AgentX when running under Windows?
12. How can I run AgentX with a different socket address?
13. How can I turn off SMUX support?
14. How can I combine two copies of the 'mib2' tree from separate subagents?
15. What traps are sent by the agent?
16. Where are these traps sent to?
17. How can I send a particular trap to selected destinations?
18. When I run the agent it runs and then quits without staying around. Why?
19. After a while the agent stops responding, and starts eating CPU time. Why?
20. How can I stop other people getting at my agent?
21. How can I listen on just one particular interface?
22. The agent is complaining about 'snmpd.conf'. Where is this?
23. Why does the agent complain about 'no access control information'?
24. How do I configure access control?
25. How do I configure SNMPv3 users?
26. The 'createUser' line disappears when I start the agent. Why?
27. What's the difference between /var/net-snmp and /usr/local/share/snmp?
28. My new agent is ignoring the old snmpd.conf file. Why?
29. Where should the snmpd.conf file go?
30. Why am I getting "Connection refused"?
31. Why can't I see values in the UCDavis 'extensible' or 'disk' trees?
32. Why can't I see values in the UCDavis 'memory' or 'vmstat' tree?
33. What do the CPU statistics mean - is this the load average?
34. How do I get percentage CPU utilization using ssCpuRawIdle?
35. What about multi-processor systems?
36. The speed/type of my network interfaces is wrong - how can I fix it?
37. The interface statistics for my subinterfaces are all zero - why?
38. Does the agent support the RMON-MIB?
39. What does "klread: bad address" mean?
40. What does "nlist err: wombat not found" (or similar) mean?
41. What does "Can't open /dev/kmem" mean?
42. The system uptime (sysUpTime) returned is wrong!
43. Can the agent run multi-threaded?
44. Can I use AgentX (or an embedded SNMP agent) in a threaded application?