Here we go:
  
1) To get cpu stuff:
  
        a) Load:
                1 minute Load: .1.3.6.1.4.1.2021.10.1.3.1
                5 minute Load: .1.3.6.1.4.1.2021.10.1.3.2
                15 minute Load: .1.3.6.1.4.1.2021.10.1.3.3
  
        b) CPU:
                percentage of user CPU time:    .1.3.6.1.4.1.2021.11.9.0
                raw user cpu time:              .1.3.6.1.4.1.2021.11.50.0
                percentages of system CPU time: .1.3.6.1.4.1.2021.11.10.0
                raw system cpu time:            .1.3.6.1.4.1.2021.11.52.0
                percentages of idle CPU time:   .1.3.6.1.4.1.2021.11.11.0
                raw idle cpu time:              .1.3.6.1.4.1.2021.11.53.0
                raw nice cpu time:              .1.3.6.1.4.1.2021.11.51.0
  
2) To get memory stuff:
  
                Total Swap Size:                .1.3.6.1.4.1.2021.4.3.0
                Available Swap Space:           .1.3.6.1.4.1.2021.4.4.0
                Total RAM in machine:           .1.3.6.1.4.1.2021.4.5.0
                Total RAM used:                 .1.3.6.1.4.1.2021.4.6.0
                Total RAM Free:                 .1.3.6.1.4.1.2021.4.11.0
                Total RAM Shared:               .1.3.6.1.4.1.2021.4.13.0
                Total RAM Buffered:             .1.3.6.1.4.1.2021.4.14.0
                Total Cached Memory:            .1.3.6.1.4.1.2021.4.15.0
  
3) To get disk:
  
        a) The snmpd.conf needs to be edited. Add the following (assuming a machine with a single '/' partition):
  
                                disk    /       100000  
  
        b) The interesting OIDs here are:
 
                Path where the disk is mounted:                 .1.3.6.1.4.1.2021.9.1.2.1
                Path of the device for the partition:           .1.3.6.1.4.1.2021.9.1.3.1
                Total size of the disk/partion (kBytes):        .1.3.6.1.4.1.2021.9.1.6.1
                Available space on the disk:                    .1.3.6.1.4.1.2021.9.1.7.1
                Used space on the disk:                         .1.3.6.1.4.1.2021.9.1.8.1
                Percentage of space used on disk:               .1.3.6.1.4.1.2021.9.1.9.1
                Percentage of inodes used on disk:              .1.3.6.1.4.1.2021.9.1.10.1
 


Let me know any ?s