Hi, When purgeUpToSnapshotIndex = false, a particularly slow follower (sync rate < write rate) can cause the RaftLog accumulates in leader and other group members. Even if they take a snapshot, they still have to keep the RaftLog for the slow follower.
When purgeUpToSnapshotIndex = true, leader will delete its RaftLog as soon as it takes the latest snapshot. Even a follower is only 100 entries behind, leader still has to send the whole snapshot to this follower. The situation worsens when snapshot contains GBs of data. Is it possible that, when the server takes a snapshot, we can ask it to preserve the latest, say, 1000 logs and purge the other logs? In this way, we don’t have to worry for RaftLog accumulation or unnecessary snapshot transfer. Regards, William Song
