[Membership] Ignore stale silos when calculating vote count requirements #9307
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…tiple hosts fail simultaneously
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'Stale' silos are likely dead, since they have not updated their
IAmAliveTimeentry in the table recently. If these silos are counted towards the voting requirement, then the cluster may enter a stalemate scenario, where active silos are not able to evict inactive silos since they would require a vote from at least one of the inactive silos.Consider this case:
In this case, the only active non-stale silo will not be able to evict the stale silos in the cluster, since it would need 2 votes to evict. Orleans calculates the voting requirement as the minimum of:
In this case, the voting requirement would be 2, since (3 + 1) / 2 = 2.
This PR changes voting requirements to exclude stale silos, reducing the requirement to 1 in our case (
(3 - 2 + 1) / 2 = 1), allowing the active silo to evict the stale silos.Microsoft Reviewers: Open in CodeFlow