[erlang-questions] HEART

Matthias Lang matthias@REDACTED
Sat May 23 22:33:05 CEST 2015

On 13. May 2015, Michael L Martin wrote:

> But who watches the watchdog?

Late reply. One approach is to have a hardware watchdog.

On the embedded system I work on, Erlang kicks a custom 'heart'
program.  The heart program kicks the hardware watchdog.

Hangs in Erlang code are dealt with by timeouts and supervisors.
Hangs in the VM are dealt with by 'heart'.
Hangs in 'heart' are dealt with by the hardware watchdog.

This approach is sufficient to make hangs an insignificant contributor
to downtime in a five-nines environment (signalling in the SS7
network), in my experience.


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