Consistency of the logs is always ensured. Faulty clocks and extreme message delays can, at worst, cause availability problems.

They are never returning an incorrect result under all non-Byzantine conditions, including network delays, partitions, and packet loss, duplication, and reordering.

As long as any majority of the servers are operational and can communicate with each other and with clients, they give proper answers. Thus, a typical cluster of five servers can tolerate the failure of any two servers. Servers are assumed to fail by stopping; they may later recover from state on stable storage and rejoin the cluster.

In the common case, a command can complete as soon as most of the cluster has responded to a single round of remote procedure calls.