[PotatoEngineer]

Probably because there's limited wireless bandwidth. It'll work, but it doesn't scale - doubly so for colocation, where other customers might eat your bandwidth. The "short distances" would help, but there might not be enough throughput to make it worthwhile.

[rurounijones]

I have always wondered why servers don't have wireless adapters for cluster heartbeats / elections / fencing etc.

With heartbeating etc. you want the minimal number of moving parts required (minimal chance of failuer).

The heartbeat is not high traffic and can be picked up by all servers in a cluster without worring about network faults.

Seems like a win-win, but then I am not a data-center expert.

[oasisbob]

Fate-sharing is one good reason. There are probably more.