swRaidMIB

		Net-SNMP-Plugin for monitoring
		Linux RAID devices

		(c) Copyright G. Kuhlmann, 2007

		This is free software. See COPYING for license.




INTRODUCTION:
============

This software is a loadable plugin module for the Net-SNMP agent to
monitor the software RAID functions of a Linux system. It works by
reading the file /proc/mdstat and providing the information read under
the ucdExperimental OID with sub-ID 18. This sub-ID hasn't been regis-
tered with anyone yet, but it was free at the time this software was
written. The plugin module provides the following read-only variable tree:


+--swRaidMIB(18)
   |
   +--swRaidTable(1)
   |  |
   |  +--swRaidEntry(1)
   |     |  Index: swRaidIndex
   |     |
   |     +-- -R-- Integer32 swRaidIndex(1)
   |     |        Range: 0..65535
   |     +-- -R-- String    swRaidDevice(2)
   |     |        Textual Convention: DisplayString
   |     |        Size: 0..255
   |     +-- -R-- String    swRaidPersonality(3)
   |     |        Textual Convention: DisplayString
   |     |        Size: 0..255
   |     +-- -R-- String    swRaidUnits(4)
   |     |        Textual Convention: DisplayString
   |     |        Size: 0..255
   |     +-- -R-- Integer32 swRaidUnitCount(5)
   |     +-- -R-- EnumVal   swRaidStatus(6)
   |              Textual Convention: RaidStatusTC
   |              Values: inactive(1), active(2), faulty(3)
   |
   +-- -R-- Integer32 swRaidErrorFlag(100)
   +-- -R-- String    swRaidErrMessage(101)
            Textual Convention: DisplayString
            Size: 0..255


swRaidTable - Contains Information about every RAID device in the system.
              It consists of the following elements:
		swRaidIndex        -  Internal index number for each device
		swRaidDevice       -  Device name (for example "/dev/md1")
		swRaidPersonality  -  RAID personality of this device (for
		                      example "Raid1")
		swRaidUnits        -  Units within this RAID device encoded
		                      as a blank-seperated string (for exam-
		                      ple "/dev/sda1 /dev/sdb1")
		swRaidUnitCount    -  Number of units in the RAID device
		swRaidStatus       -  Status of the RAID device. This can be
		                      one of: inactive, active, faulty

swRaidErrorFlag - Contains a non-zero value if any of the RAID devices on the
                  system is faulty

swRaidErrMessage - Contains the names of all faulty RAID devices in case the
                   swRaidErrorFlag is non-zero

The swRaidErrorFlag and swRaidErrMessage variables are primarily provided to
get a quick overview of the RAID system, for example by the use of an auto-
mated monitoring script. They can also be used to generate SNMP trap or inform
messages in case one or more of the RAID devices failed.



REQUIREMENTS:
============

To use this plugin module you obviously need a somewhat current Net-SNMP
agent. It has been tested with Net-SNMP version 5.4. I don't know if it
works with any older version. The agent has to be compiled with support
for loadable modules (which is the default). In addition the Net-SNMP
runtime libraries and include files have to be installed in order to
compile the module.



INSTALLATION:
============

The swRaidMIB plugin module is not a huge software project, so
no configure script has been written. Since this module only makes
sense on a Linux system, and gcc is usually installed on such a
system, the Makefile has been written to only support the GNU
development tools. To compile on other Unix-like systems you would
probably need to modify the Makefile. Therefore, to install this
module, first run "make" in the source directory. Then copy the
resulting file swRaidPlugin.so to a place where the SNMP agent
can find it, for example /usr/lib/snmp/dlmod. Also copy the MIB
file named SWRAID-MIB.txt to the place where all your other MIB
files are stored, usually something like /usr/local/share/netsnmp/mibs
or /usr/share/snmp/mibs.

In order for the SNMP agent to find the module you need a line in
the snmpd configuration file telling it to load the module:

dlmod swRaidMIB /usr/lib/snmp/dlmod/swRaidPlugin.so

Now modify the snmpd startup script (depending on your distribution)
to start the agent with the additional command line option

-m+SWRAID-MIB

which causes the agent to load the SWRAID-MIB in addition to all the
other internal MIBs, and restart snmpd. You can now view the RAID data
using your preferred SNMP client program, like mbrowse or snmpwalk.
Depending on your security policies you can try the following command:

snmpwalk -v1 -c public -m+SWRAID-MIB localhost swRaidMIB

This should show you the same information you can get from the /proc/mdstat
file. The plugin module will re-read /proc/mdstat at most once every 60
seconds. If you want to test the module, set one of the RAID drives to a
faulty state (for example using the mdadm program) and wait a minute until
you can see the result through SNMP.



SUPPORT:
=======

If you need any help using this module, or you find a bug please let me
know. Also, if you can think of any improvement or even have implemented
any improvement yourself please send me an E-Mail to:

gero@gkminix.han.de

Please note that I wrote this program in my spare time, so answers may
sometimes take a bit longer. I will not offer any commercial support for
this program.