The Backup session log shows:
...
YYYY-MM-DD HH:MM:SS INFO: [167] Creating snapshot of virtual machine ...
YYYY-MM-DD HH:MM:SS ERROR: [167] Unable to create non-quiesced snapshot after a retry attempt: Detected an invalid snapshot configuration.
YYYY-MM-DD HH:MM:SS ERROR: [167] Unable to create snapshot.
YYYY-MM-DD HH:MM:SS INFO: [167] Enabling storage migration of virtual machine ...
YYYY-MM-DD HH:MM:SS INFO: [167] Storage migration successfully enabled: "vm-4030" @ "my_vm_name.my_domain.com"
YYYY-MM-DD HH:MM:SS WARN: [167] Virtual machine left locked by backup session because cleanup is required. Snapshot was not removed.
...
The VMNAME_vmware-###.log shows:
...
YYYY-MM-DD HH:MM:SS| vcpu-0| I125: SNAPSHOT: SnapshotBranchDisk: Failed to branch disk: '/vmfs/volumes/DATASTORE_UUID/VM_NAME/VM_NAME.vmdk' -> '/vmfs/volumes/DATASTORE_UUID/VM_NAME/VM_NAME-000004.vmdk' : The file already exists (39)
YYYY-MM-DD HH:MM:SS| vcpu-0| I125: DiskLib_IsVMFSSparseSupported: vmfssparse is not supported on /vmfs/volumes/DATASTORE_UUID/VM_NAME: f532.
YYYY-MM-DD HH:MM:SS| vcpu-0| I125: DISKLIB-LIB_CREATE : DiskLibCreateCreateParam: Selecting the default child type as SeSparse for /vmfs/volumes/DATASTORE_UUID/VM_NAME/VM_NAME-000005.vmdk.
YYYY-MM-DD HH:MM:SS| vcpu-0| I125: DISKLIB-LIB_CREATE : DiskLibCreateCreateParam: seSparse grain size is set to 8 for '/vmfs/volumes/DATASTORE_UUID/VM_NAME/VM_NAME-000005.vmdk'
YYYY-MM-DD HH:MM:SS| vcpu-0| I125: SNAPSHOT: SnapshotBranchDisk failed for '/vmfs/volumes/DATASTORE_UUID/VM_NAME/VM_NAME.vmdk' : A required file was not found (7).
YYYY-MM-DD HH:MM:SS| vcpu-0| I125: DISKLIB-VMFS : "/vmfs/volumes/DATASTORE_UUID/VM_NAME/VM_NAME-flat.vmdk" : closed.
YYYY-MM-DD HH:MM:SS| vcpu-0| I125: SNAPSHOT: SnapshotBranch failed: A required file was not found (7).
...
The issue can occur when there are are orphaned temporary snapshot descriptor files in the virtual machine data store directory. These snapshot descriptor files appear as ####.-000001.vmdk, ####.-000001-sesparse.vmdk and ####.-000001-ctk.vmdk.
The steps to remove the orphaned temporary snapshot descriptor files are documented in VMware Knowledge base 80246.
https://kb.vmware.com/s/article/80246
- Browse affected VM's Datastore to identify the temporary descriptor files. Name may appear as:
- ####-000001.vmdk
- ####-000001-sesparse.vmdk
- ####-000001-ctk.vmdk
- Identify a folder with enough space to move the temporary descriptor files and create a new folder
- vmfs/volumes/VM_####_DATASTORE5/FOLDERNAME/
- Move the temporary descriptor files to newly created folder
- Take snapshot of the VM and validate snapshot created successfully.
- Delete all the snapshots with the "Delete All Snapshots" option.
- Validate snapshot deleted.
- Validate there are no descriptor files in the VM datastore folder.
- Let the scheduled vProxy Backups Run.