[mrtg] Multiple OID's in expression...

[David Mitchell]

I want to calculate the percentage memory usage on a cisco router. There are
2 areas of memory and the figures for memory in use and memory free are
stored in a table.

The table oid is 1.3.6.1.4.1.9.9.48.1.1.

And the OID's I want to use are:
1.3.6.1.4.1.9.9.48.1.1.1.5.1 Proc mem in use
1.3.6.1.4.1.9.9.48.1.1.1.6.1 Proc Mem free
1.3.6.1.4.1.9.9.48.1.1.1.5.2 IO mem in use
1.3.6.1.4.1.9.9.48.1.1.1.6.2 IO mem free.

(Proc mem is row 1 in the table, IO mem is row 2, element 5 is memory in
use, element 6 is free memory)

So I want to calculate 100*mem in use / (mem in use + mem free) and use the
Proc mem as the 'in' value and IO mem as the 'out' value so they appear on
the same graph.

The original target I used was:
Target[$target_name]: 1.3.6.1.4.1.9.9.48.1.1.1.5.1 *
00/( 1.3.6.1.4.1.9.9.48.1.1.1.5.1 + 1.3.6.1.4.1.9.9.48.1.1.1.6.1 ) &
1.3.6.1.4.1.9.9.48.1.1.1.5.2 *100/( 1.3.6.1.4.1.9.9.48.1.1.1.5.2 +
1.3.6.1.4.1.9.9.48.1.1.1.6.2 ):routeraddress

I know (and have tried) that I need to add the router address to each OID,
however I cannot get the expression to evaluate, the best I have acheived is
to get a 0 result! Most variations on the target line cause rateup to
abort...!

I have put debugging on MRTG but it didn't help - I cannot see each variable
being read, just the result of 'getcurrent'. How is the expression
evaluated in MRTG (Where?) - I am learning enough PERL to be able to
understand some of what is going on.

TIA

David

[Sawyer, David]

For easy viewing, lets say...
OID1 = .5.1 Proc mem in use
OID2 = .6.1 Proc Mem free
OID3 = .5.2 IO mem in use
OID4 = .6.2 IO mem free.

You want...

OID1/(OID1+OID2))*100
460 /(460 + 564))* 100 = 46%

So for your target you should try...

Target[Proc_IO] (OID1&OID3:***@host /
(OID1&OID3:***@host +
OID2&OID4:***@host)) * 100

Let me know if this works.



Dave

-----Original Message-----
From: David Mitchell [mailto:***@sunman.co.uk]


I want to calculate the percentage memory usage on a cisco router.

The table oid is 1.3.6.1.4.1.9.9.48.1.1.

And the OID's I want to use are:
1.3.6.1.4.1.9.9.48.1.1.1.5.1 Proc mem in use
1.3.6.1.4.1.9.9.48.1.1.1.6.1 Proc Mem free
1.3.6.1.4.1.9.9.48.1.1.1.5.2 IO mem in use
1.3.6.1.4.1.9.9.48.1.1.1.6.2 IO mem free.

So I want to calculate 100*mem in use / (mem in use + mem free) and use the
Proc mem as the 'in' value and IO mem as the 'out' value so they appear on
the same graph.

The original target I used was:
Target[$target_name]: 1.3.6.1.4.1.9.9.48.1.1.1.5.1 *
00/( 1.3.6.1.4.1.9.9.48.1.1.1.5.1 + 1.3.6.1.4.1.9.9.48.1.1.1.6.1 ) &
1.3.6.1.4.1.9.9.48.1.1.1.5.2 *100/( 1.3.6.1.4.1.9.9.48.1.1.1.5.2 +
1.3.6.1.4.1.9.9.48.1.1.1.6.2 ):routeraddress


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[David Mitchell]

Thanks David - that worked fine, I hadn't picked up that you put the OID's
in the expression in pairs rather than pairing the expressions

Ie it is OID1&OID2:router + OID3&OID4:router

rather than

OID1:router + OID3:router & OID2:router + OID4:router

David