[mrtg] warning: expected a number but got 'C:'

[Stuart Kendrick]

hi,

i'm trying to trend variables from WTCS's INFORMANT-STD MIB

guru> snmpget -c public shiva .1.3.6.1.4.1.9600.1.1.1.1.2.2.67.58
INFORMANT-STD::lDiskPercentDiskReadTime."C:" = Gauge32: 0
guru>  snmpget -c public shiva .1.3.6.1.4.1.9600.1.1.1.1.6.2.67.58
INFORMANT-STD::lDiskPercentIdleTime."C:" = Gauge32: 99
guru>

but when i include these in an MRTG config file:

[...]
#### lDiskPercentDiskReadTime vs lDiskPercentIdleTime ####
Target[test-box_wtcsDiskReadTimeC:]:.1.3.6.1.4.1.9600.1.1.1.1.2.2.67.58&.1.3.6.1.4
.1.9600.1.1.1.1.6.2.67.58:public at shiva:::::2
MaxBytes[test-box_wtcsDiskReadTimeC:]:100
Options[test-box_wtcsDiskReadTimeC:]:gauge
[...]


i see the following in ../var/log/shiva.log:

2007-02-11 00:52:51 -- SNMP Error:
Received SNMP response with error code
   error status: genErr
   index 2 (OID: 1.3.6.1.4.1.9600.1.1.1.1.6.2.67.58)
SNMPv2c_Session (remote host: "shiva" [10.10.14.24].161)
                    community: "public"
                   request ID: 43937163
                  PDU bufsize: 8000 bytes
                      timeout: 2s
                      retries: 5
                      backoff: 1)
  at /opt/local/mrtg-2/bin/../lib/mrtg2/SNMP_util.pm line 490
2007-02-11 00:52:51 -- SNMPGET Problem for
.1.3.6.1.4.1.9600.1.1.1.1.2.2.67.58 .
1.3.6.1.4.1.9600.1.1.1.1.6.2.67.58 on public at shiva:::::2:v4only
  at /opt/local/mrtg-2/bin/mrtg line 2149
[...]
2007-02-11 00:52:52 -- 2007-02-11 00:52:50: WARNING: Expected a number
but got 'C:'
[...]


i can see, in a packet dump of the get-response from shiva, the string
"C:" ... so i'm guessing that MRTG doesn't like the way the agent is
returning a string within the OID

from wireshark decode window:

[...]
name: 1.3.6.1.4.1.9600.1.1.1.1.2.2.67.58
(SNMPv2-SMI::enterprises.9600.1.1.1.1.2.2.67.58)

from wireshark hex decode window ... the string from 4B - 59 is hi-lit,
when i highlight the 'name:' string above ... notice the 'C:' at the end
of the ASCII decode window


0000   00 13 72 88 ea bd 00 07 84 7a b0 00 08 00 45 00  ..r......z....E.
0010   00 4f 9a b7 00 00 7b 11 5a 90 8c 6b e7 04 8c 6b  .O....{.Z..k...k
0020   4a 7b 00 a1 ee 14 00 3b c4 42 30 31 02 01 01 04  J{.....;.B01....
0030   06 70 75 62 6c 69 63 a2 24 02 04 38 3b 03 85 02  .public.$..8;...
0040   01 00 02 01 00 30 16 30 14 06 0f 2b 06 01 04 01  .....0.0...+....
0050   cb 00 01 01 01 01 02 02 43 3a 42 01 00           ........C:B..

see https://vishnu.fhcrc.org/mrtg/mrtg-wtcs-error.pdf for a screen dump
of this packet

in fact, i myself find this puzzling.  i thought that agents always
returned strings of dotted numbers ... and that the manager was
responsible for decoding these into strings, like "C:", if that is
appropriate.  but, obviously, i'm mistaken

i don't even know what to call this problem, how to label it.  any hints
on what is happening here?

--sk

stuart kendrick
fhcrc