Dell PowerEdge XR4000w Installation and Service Manual

The Witness “Heart Beat” is a feature that is enabled through the Dell OS Agent for Witness (DOSA-W) which resides on the Witness host. Usage of the Heart Beat requires a properly deployed DOSA-W driver to the Witness host (Witness DOSA-W deployment for deployment information).

The Witness Heart Beat is a regular pulse that the CM receives from the Witness OS every 60 seconds. The iDRAC of connected compute sleds supports a Heart Beat monitor feature which is disabled by default. If there are no compute sleds in the chassis, the Chassis Manager disables this feature by default as well.

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When the Heart Beat functionality is enabled through iDRAC, the CM behavior is as follows:

• After Witness power-on, CM waits five minutes for BIOS load and Witness OS boot.
• After five minutes (or if heartbeat monitoring is switched to “Enabled” through iDRAC during this period), a three minute watchdog timer starts.
• Every 60 seconds, the heartbeat pulse send from the Witness host will reset the watchdog timer.
• If the watchdog timer expires, the CM will cold-reboot the Witness.
  NOTE:This cold-reboot cannot occur more than three times in a 24-hour period; any additional expiry of the watchdog timer will only log an error in iDRAC.