Cheshire Cat Computing

Is it possible to use SNMP queries to set things other than Tartget[]?

For example, can one use an SNMP query for MaxBytes[]? There are several IODs that provide the size of the variable (hrStorageSize, memTotalAvail, ifSpeed, and the like).

Although the cfgmaker script uses SNMP to find out the value of MaxBytes on creation of the cfg file, MRTG cannot use SNMP for this as it is liable to change. The MaxBytes value needs to be configured in the RRD file (it is a validity threshold) and so needs to be fixed.

Also, Routers2 uses this value for many things and if it were an SNMP lookup it would require many SNMP lookups to be done at display time which may block. If the device were down, there would be no way to query it via SNMP, so we wouldnt know MaxBytes, so we couldnt display the stored data...

Having said this, MRTG does re-tune the RRD if it finds that MaxBytes value does not match the maxbytes as configured in the RRD. So, it might be possible to make MRTG do an SNMP query instead, and Routers2 could be set to read the RRD maxbytes instead of making an SNMP lookup. These would be major changes though, and would need to start with MRTG... they would also potentially break many other 3rd-party MRTG utilities.

Steve

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Steve Shipway
UNIX Systems, ITSS, University of Auckland, NZ
Woe unto them that rise up early in the morning... -- Isaiah 5:11