Backup Fails for a Migrated ZStack VM Due to qcow2 Snapshot Error

Damian Montrose

I’m trying to back up a specific VM in ZStack, but the backup keeps failing. The run log shows:

VM HokBen Wazuh' backup failed,[#4]Invalid parameter
And the backup server logs show:

[ERROR:4#Parameter invalid]: send get multiple cluster content error. kvm/kvm_disk_rpc_client.cpp:3008:RpcReadMutiMappedClustersV3
2023/09/07 16:48:19 backup_server [WARN:4#Parameter invalid]: read multiple cluster data error, disk_id: /zstack_ps/rootVolumes/acct-48c901f04906422e8834682ac9bb726d/vol-c0da980cf4c24d15a06e4e43875d2f09/snapshots/3f5499ba940d4679af3d83dac9e6bf61.qcow2, storage_id: 8df0ff25658c4a1198349f189eb24afd, storage_type: 1, cluster_vector_num: 4, errno: 11, cluster_size: 1048576.

The VM was migrated from VMware manually. The backup task just won’t complete. Has anyone seen this before?

Dan Zeng

Damian Montrose
Hi, there,
Yes, this happens when a VM migrated from another platform (like VMware) has its disk in qcow2 format. ZStack can’t locate the snapshot information correctly, which causes the backup failure.

In version 702, this issue has been fixed. For existing cases, you can convert the original VM disk to qcow2 and then retry the backup. The error occurs because the qcow2 file name in the system doesn’t match the actual file path, leading to parameter retrieval errors.

Alternatively, you can perform cross-platform migration using Vinchin to solve the problem directly.

Damian Montrose

Thanks a lot for the detailed explanation! 🙏
I’ll try converting the VM disk to qcow2 and see if that resolves the backup issue. Appreciate your help!