Quorum

Meaning of the word

It's important to keep in mind that this word in Latin isn't even a noun.

"I appoint these 20 people to oversee the trial, of whom (quorum) I require at least 5 to be present to make it official." Here, of whom which is a relative pronoun is simply used in English to represent the minium required people or votes.

Just the entire statement is now simply referred by the word "quorum" in English. We "wait" for the quorum, we "require" the quorum, we "need" the quorum, we "have" the quorum, we "don't have" the quorum.

Quorum is used in the context of distributed systems in two different ways.

1. Where we've multiple replicas of the same data and we need to read or write to a minimum number of replicas to ensure consistency.
2. Where we've multiple nodes in a cluster and we need to ensure that a minimum number must exist.
3. We need a minimum number of votes to elect a leader in a cluster.