Summary

**WiredTiger backup doesn't contain the WiredTiger.turtle file to identify the source of the backup.

Motivation

Does this affect any team outside of WT?

NO.

How likely is it that this use case or problem will occur?

As part of the recent WT-8395, WiredTiger detects the corresponding database files versions and don't perform the RTS using the checkpoint snapshot, but it cannot perform the same with backup restore recovery.

If the problem does occur, what are the consequences and how severe are they?

It can't cause any problems other than MongoDB versions 4.4.2 to 4.4.4

Is this issue urgent?

No.

Acceptance Criteria (Definition of Done)

1. Design and get an agreement after designing the solution
2. Implement: Store the WiredTiger version either the WiredTiger.wt metadata file or copy the WiredTiger.turtle file along with the backup files.

Testing

Currently, there are no uses with the saved WiredTiger version information in the backup. It is not possible to write an automated test against the change.

Documentation update

NO.

Suggested Solution

I prefer a solution of saving the WiredTiger version in the WiredTiger metadata every time when the checkpoint happens. This information is automatically copied into the backup.