[ZOOKEEPER-3056] Fails to load database with missing snapshot file but valid transaction log file

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 3.5.3, 3.5.4
• Fix Version/s: 3.6.0, 3.5.6
• Component/s: server
• Labels: pull-request-available
• Assignee: Michael Han
• Reporter: Michael Han
• Created: 05/Jun/18 15:03
• Updated: 19/Dec/20 07:59
• Resolved: 03/Sep/19 06:54

Description

An issue was reported when a user failed to upgrade from 3.4.10 to 3.5.4 with missing snapshot file.

The code complains about missing snapshot file is here which is introduced as part of ZOOKEEPER-2325.

With this check, ZK will not load the db without a snapshot file, even the transaction log files are present and valid. This could be a problem for restoring a ZK instance which does not have a snapshot file but have a sound state (e.g. it crashes before being able to take the first snap shot with a large snapCount parameter configured).

 

how to use this fix

Add zookeeper.snapshot.trust.empty=true to your server configuration file and start the server.

This property will skip the check.

It is recommended to remove the property once you have a working server, because that check is important to ensure that the system is in good shape

Issue Links

• is related to: ZOOKEEPER-3644 Data loss after upgrading standalone ZK server 3.4.14 to 3.5.6 with snapshot.trust.empty=true
• is required by: ZOOKEEPER-2325 Data inconsistency if all snapshots empty or missing
• is required by: ZOOKEEPER-3513 Zookeeper upgrade fails due to missing snapshots
• relates to: ZOOKEEPER-4005 Zookeeper will not sync snapshot while get DIFF and cause start failed.
• links to: GitHub Pull Request #1069
• links to: GitHub Pull Request #1072
• links to: GitHub Pull Request #1178