[HBASE-8459] make online region snapshotting based on region names instead of region server names

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 0.94.6.1, 0.95.0
• Component/s: snapshots
• Assignee: Unassigned
• Reporter: Jonathan Hsieh
• Created: 29/Apr/13 22:12
• Updated: 16/Jun/22 16:52
• Resolved: 16/Jun/22 16:52

Description

Currently, online snapshots assign work by region server. This works when regionseveers do not fail or moved regions. In 0.95+, the table locks prevent moves while snapshotting is in progress but a failed RS during a snapshot may still fail in the verification step. This is because the failure would trigger an assignment which may occur after the work for the regionserver is determined, leaving some regions unsnapshotted, thus leaving it to fail in the verification step.

If we instead assigned snapshotting work by region name, a moved region could be snapshotted by the newly assigned region server.