title: Checks the PSU sensors on Dell PowerConnect Switches
agents: snmp
author: Chris Bowlby <cbowlby@tenthpowertech.com>
license: GPL
distribution: check_mk
description:
 This check monitors the various PSU sensors on a Dell PowerConnect switch that supports
 the DELL-VENDOR-MIB. It will monitor the state of the PSU itself, depending on the
 state returned by the PSU.

 If a switch has more then one PSU sensor, it will create a service for EACH sensor.
 However, if a switch has any PSU units that are not connected up to the sensor suite, or
 there is an empty PSU bay, they will not be ignored by this check.

 A PSU that is running normally will return an OK nagios state. Any PSU that
 are in a warning or is not present (if it was previously present) will return a WARNING
 nagios state. If a PSU is in a critical or is non-functional according to the sensor will
 return a CRITICAL nagios state. Lastly, if a PSU is in a "shutdown" state, it will return
 an UNKNOWN nagios state.

 The service will show the state of the PSU, as well as the power source state. The source
 of the power can be one of the following:

 - Unknown
 - Alternating Current
 - Direct Current
 - External Power Supply
 - Internal Redundant

 Currently, testing has been completed with the Dell PowerConnect 5448 and 5424 models,
 however the service check may work with other models.

perfdata:
 Each PSU sensor uses a single variable value (0..1) representing
 the state of the PSU itself. A 1 represents a normal "ON" state, where as
 a 0 represents any "OFF", which can mean warning, critical, shutdown,
 not present (only if previously present), or not functioning. This is simply
 to chart the state of the PSU itself.

inventory:
 During the inventory phase of check_mk, it will create one or more service {Sensor psX_unitX}
 entries, as long as the MIB defined above is supported on the switch.

example:
 If a switch has 2 PSU devices in the device, it may create one service for each PSU, or a single
 service that indicates the PSU devices are connected internally, in a redundant state. The
 result is strictly determined in what the SNMP service provides to the check.

 The psX value represents the selected PSU, where as the unitX values represents the sensor
 assigned to the PSU. It is possible to have multiple sensors on a single PSU, though I have
 yet to see one.