[IGNITE-17253] Support for snapshot streaming in RAFT state machine

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Labels: ignite-3
• Epic Link: Storage support for Rebalancing
• Assignee: Unassigned
• Reporter: Roman Puchkovskiy
• Created: 28/Jun/22 18:16
• Updated: 06/Oct/22 10:12
• Resolved: 06/Oct/22 10:12

Description

In JRaft, snapshotting works through files: first, a snapshot is written to a file, later it is sent to follower(s).

This requires additional FS space, and it is a bit strange for in-memory cases.

We need to switch to streaming way of doing snapshots: when the leader needs to bootstrap a follower, it opens a 'channel' to the follower, starts producing a snapshot and streaming it to the follower. The follower applies the snapshot in the same streaming way.

This ticket is about modifying JRaft internal infrastructure to switch to snapshot streaming.

See IGNITE-17083

Issue Links

• split from: IGNITE-17083 Base classes for full rebalance procedure