v.20.1Improvement

Added MergeTree Disk Check to Prevent Data Loss

Added check for extra parts of MergeTree at different disks, in order to not allow to miss data parts at undefined disks. #8118 (Vladimir Chebotarev)
Added a validation check to ensure extra parts of MergeTree tables are not distributed across different disks to prevent missing data parts.

Why it matters

This feature addresses the issue of potential data loss or inconsistency caused by parts of MergeTree tables being stored on undefined or different disks. By enforcing this check, it guarantees data integrity and consistency, avoiding scenarios where parts could be misplaced or overlooked in multi-disk setups.

How to use it

The check is applied automatically when managing MergeTree tables. Users do not need to enable it explicitly; it ensures that all data parts reside on defined disks, alerting or preventing operations that would result in parts being placed on undefined disks.