I'm doing just that on some linux servers - running 7.1.4 on Win2k server.
Here is the entry that must be added to mibexpr.conf ....

StorageUtil \
"100* hrstorageused / hrstoragesize" \
        .1.3.6.1.2.1.25.2.3.1.6. \
        .1.3.6.1.2.1.25.2.3.1.5. / \
        100 *
One can then set up a collection using the snmpcollect GUI which writes to 
snmpcol.conf.
Here is a corresponding entry from snmpcol.conf ....

MIB StorageUtil 1 RootStorageUtil units EXPRESSION R senetmon02 C 
linuxserver.mycorp.com 0xffffffff 300 > 80.000000 <= 75.000000 % s 58720263

This sends a trap 58720263 (Netview ColDetThresh) when utilisation exceeds 80%.
Utilisation data can be obtained by querying the sql database.


-----Original Message-----
From: owner-nv-l AT lists.us.ibm DOT com [mailto:owner-nv-l AT lists.us.ibm DOT 
com]On
Behalf Of John Creasey
Sent: Saturday, 22 October 2005 12:21 PM
To: nv-l AT lists.us.ibm DOT com
Subject: [nv-l] Collecting data from Mib Expressions


I have created a Mib expression to tell me disk utilisation.
Unfortunately no matter what I try I can't seem to get it to either raise a
threshold trap or to be collected by snmpCollect.

I'm sure I am probably missing something fairly obvious.  Has anyone had any
luck with these things?   How can you test them, and is it possible to
collect the results using snmpCollect.

Regards,
John.


************************************************************************
*PLEASE NOTE*  This email and any attachments may
be confidential. If received in error, please delete all
copies and advise the sender. The reproduction or
dissemination of this email or its attachments is
prohibited without the consent of the sender.

WARNING RE VIRUSES:  Our computer systems sweep
outgoing email to guard against viruses, but no warranty
is given that this email or its attachments are virus free.
Before opening or using attachments, please check for
viruses.  Our liability is limited to the re-supply of any
affected attachments.

Any views expressed in this message are those of the
individual sender, except where the sender expressly,
and with authority, states them to be the views of the
organisation.
************************************************************************