OpenNMS monitor disk space usage by SNMP

#==Overview
This post demonstrates two ways to monitor disk space usage by 2 different SNMP MIBS
1) .iso.org.dod.internet.private.enterprises.ucdavis.dskTable
2) .iso.org.dod.internet.mgmt.mib-2.host.hrStorage

What is the diffrence? Option #1 requires disk path to be hardcoded in snmpd.conf at target system, But Option #2 can monitor all partions by default, even there is need to monitor specific partions, the filter is set on OpenNMS, not target system, So Option #2 is more flexible

The alarm is triggered by threshold in SNMP, so you don't need to setup monitors to trigger alarm. Firstly, Please make sure you have basic snmp working, refer to my post Set up Net-snmp on CentOS

#==ENV
OpenNMS 1.6.2 + Centos 5.2 +net-snmp 5.3.1

#==(1) Monitor disk space usage by dskTable MIB
add the parttiton to be monitored to snmpd.conf
$vi /etc/snmp/snmpd.conf
disk /opt2

#====Test by snmpwalk first

$snmpwalk -v2c 172.16.31.3 -c public .iso.org.dod.internet.private.enterprises.ucdavis.dskTable

UCD-SNMP-MIB::dskPath.1 = STRING: /opt2 

OpenNMS 1.6.2 has set default threshold, so you don't need to config any thing in openNMS. doublecheck the threshold by
GUI->Admin->Manage Thresholds->netsnmp

#====Sample alarm appeared
High threshold exceeded for SNMP datasource ns-dskPercent on interface 172.16.31.3, parms: ds="ns-dskPercent" value="100.0" threshold="90.0" trigger="2" rearm="75.0" label="/opt2" ifIndex="2

#== (2) Monitor disk space usage by hrStorage MIB
no need to add disk path to snmpd.conf, but openNMS needs to be customized.

#===Test by snmpwalk first

$snmpwalk -v2c 172.16.31.3 -c public .iso.org.dod.internet.mgmt.mib-2.host.hrStorage

#==== Find systemOID
This OID is the same to all Net-SNMP agent

$snmptranslate .iso.org.dod.internet.private.enterprises.netSnmp.netSnmpEnumerations.netSnmpAgentOIDs -On

.1.3.6.1.4.1.8072.3.2

#==== Include the SysOID to ./etc/datacollection-config.xml
By default, mib2-host-resources-storage is not included for Net-SNMP
The value in sysoidMask should include your systemOID
For example sysoidMask .1.3.6.1.4.1.8072.3. includes .1.3.6.1.4.1.8072.3.2

systemDef name="Net-SNMP"
        sysoidMask.1.3.6.1.4.1.8072.3./sysoidMask
        collect
          ...
 includeGroup mib2-host-resources-storage/includeGroup

#====Include your sysOID to ./etc/threshd-configuration.xml

package name="hrstorage"
         filterIPADDR != '0.0.0.0' & (nodeSysOID LIKE '.1.3.6.1.4.1.8072.3.2.%'  nodeSysOID LIKE '.1.3.6.1.4.1.311.%'   nodeSysOID LIKE '.1.3.6.1.4.1.2.3.1.2.1.1.3.%')/filter
..
  /package

OpenNMS 1.6.2 has set default threshold, doublecheck the threshold by
GUI->Admin->Manage Thresholds->hrStorage

By default, it monitors all partions. You can create filter to monitor specific partions only

#===Sample alarm appeared
High threshold exceeded for SNMP datasource hrStorageUsed / hrStorageSize * 100.0 on interface 172.16.31.3, parms: ds="hrStorageUsed / hrStorageSize * 100.0" value="94.88754412506304" threshold="90.0" trigger="2" rearm="75.0" label="/opt2" ifIndex="2"