Scenario

• Product: ZCF
• Component: ZStack Cloud
• Version: 4.8.x
• Deployment: Dual management nodes
• Trigger: A sharedblock volume installation path differs from its snapshot path and requires database-metadata correction.

Symptoms

• A volume installation path is inconsistent.
• The current snapshot path and volume path point to different objects.
• Volume metadata and snapshot-tree metadata must both be checked.

Assessment

1. Check the target volume installPath in VolumeVO.
2. Check treeUuid, parentUuid, and latest for related snapshots.
3. When a snapshot tree has multiple records, identify the snapshot chain to retain.

Cause

An inconsistent volume installation path requires direct correction of volume-path metadata and cleanup of abnormal snapshot-tree references so that the volume and snapshot chain are consistent.

Resolution

1. Preparation

• Risk level: High.
• Disable global ZStack Cloud high availability.
• Back up databases on both management nodes.
• This procedure changes database entries; strictly verify UUIDs and paths.

2. Disable high availability and back up the database:

~~~bash zstack-ctl dump_mysql ~~~

• Expected result: A rollback baseline is available.

3. Query the current volume path:

~~~sql select * from VolumeVO where uuid='8b389dfd74f84e0f9d5edc15e99b3cbc'\\G; ~~~

• Expected result: It is clear whether the current installPath differs from the expected path.

4. Correct the volume path:

~~~sql update VolumeVO set installPath = 'sharedblock://f9c3c78f7674441ba97003c0b21265c8/97793a14251b4c9684d03b9ec87f406f' where uuid = '8b389dfd74f84e0f9d5edc15e99b3cbc'; ~~~

• Expected result: The volume metadata path is corrected.

5. Query the treeUuid for the abnormal snapshot:

~~~sql select from VolumeSnapshotVO where uuid="ed4372d07adf41e8b6cc2afce65a18b1"\\G; select from VolumeSnapshotVO where treeUuid="ba19dff9e5d44c8d9594b1dd828e63d9"\\G; select from VolumeSnapshotTreeVO where uuid="ba19dff9e5d44c8d9594b1dd828e63d9"\\G; select from VolumeSnapshotReferenceVO where referenceUuid="ba19dff9e5d44c8d9594b1dd828e63d9"\\G; ~~~

• Expected result: The snapshot-tree structure and references are identified.

6. If the current treeUuid contains multiple snapshots, delete the abnormal snapshot:

~~~sql delete from VolumeSnapshotVO where uuid="ed4372d07adf41e8b6cc2afce65a18b1"; ~~~

• Expected result: The abnormal snapshot record is removed.

7. Query the remaining parentUuid and snapshot chain:

~~~sql select from VolumeSnapshotVO where treeUuid="ba19dff9e5d44c8d9594b1dd828e63d9"\\G; select from VolumeSnapshotVO where uuid="8eded03f3c394dfdbf68f1313a2bbe32"; ~~~

• Expected result: The snapshot record to retain is identified.

8. Set the retained snapshot latest value to true:

~~~sql Update VolumeSnapshotVO set latest=true where uuid="8eded03f3c394dfdbf68f1313a2bbe32"; ~~~

• Expected result: Snapshot-tree state is consistent.

9. Enable global high availability.

• Expected result: Normal platform operation is restored.

Verification

• Verify that VolumeVO installPath is the correct path.
• Verify that abnormal snapshots are removed from the snapshot tree.
• Verify that the retained snapshot has the correct latest flag.
• Verify normal platform and workload operation.

Risks and rollback

• Risk: Incorrect UUID validation before direct metadata update or deletion can damage a volume or snapshot chain.
• Risk level: High.
• Rollback: Restore the database backup directly.