NVP-vProxy FLR mount generates "failed to add disk scsi0:3" due to disk sector descriptor

Summary: The NetWorker VMware Protection (NVP) solution is configured with the vProxy Appliance. A file-level restore (FLR) fails to mount one of the virtual disk (.vmdk) files to any target virtual machine (VM) for the file restore. ...

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Symptoms

The FLR Mount session log shows: 
...
YYYY-MM-DD HH:MM:SS INFO:   [@(#) Build number: 66] Adding VMDKs to VM 'VM_NAME' (vm-45)
YYYY-MM-DD HH:MM:SS ERROR:  [@(#) Build number: 66] AddDevice failed for '[EMC-FLR-col636-1636572731] vm-45-disk-key-2002.vmdk': Failed to add disk scsi0:3.
YYYY-MM-DD HH:MM:SS INFO:   [@(#) Build number: 66] Unmounting after mount failure: Unable to add VMDKs [[EMC-FLR-col636-1636572731] vm-45-disk-key-2002.vmdk [EMC-FLR-col636-1636572731] vm-45-disk-key-2000.vmdk [EMC-FLR-col636-1636572731] vm-45-disk-key-2001.vmdk] to VM 'VM_NAME' (vm-45): AddDevice failed for '[EMC-FLR-col636-1636572731] vm-45-disk-key-2002.vmdk': Failed to add disk scsi0:3.
...

The target vmware-0.log shows: 
...
YYYY-MM-DD HH:MM:SS| vmx| I005: HotAdd: Adding scsi-hardDisk with mode 'independent-persistent' to scsi0:3
YYYY-MM-DD HH:MM:SS| vmx| I005: DISK: OPEN scsi0:3 '/vmfs/volumes/99206132-dbc3fe7d/vm-45-disk-key-2002.vmdk' independent-persistent R[]
YYYY-MM-DD HH:MM:SS| vmx| I005: DISKLIB-VMFS  : VmfsExtentCommonOpen: possible extent truncation (?) realSize is 5733781340, size in descriptor 5733781341.
YYYY-MM-DD HH:MM:SS| vmx| I005: DISKLIB-VMFS  : "/vmfs/volumes/99206132-dbc3fe7d/vm-45-disk-key-2002-flat.vmdk" : failed to open (The file specified is not a virtual disk): Size of extent in descriptor file larger than real size. Type 3
YYYY-MM-DD HH:MM:SS| vmx| I005: DISKLIB-LINK  : "/vmfs/volumes/99206132-dbc3fe7d/vm-45-disk-key-2002.vmdk" : failed to open (The file specified is not a virtual disk).  
YYYY-MM-DD HH:MM:SS| vmx| I005: DISKLIB-CHAIN : "/vmfs/volumes/99206132-dbc3fe7d/vm-45-disk-key-2002.vmdk" : failed to open (The file specified is not a virtual disk).
YYYY-MM-DD HH:MM:SS| vmx| I005: DISKLIB-LIB   : Failed to open '/vmfs/volumes/99206132-dbc3fe7d/vm-45-disk-key-2002.vmdk' with flags 0xa The file specified is not a virtual disk (15).
YYYY-MM-DD HH:MM:SS| vmx| I005: DISK: Cannot open disk '/vmfs/volumes/99206132-dbc3fe7d/vm-45-disk-key-2002.vmdk': The file specified is not a virtual disk (15).
YYYY-MM-DD HH:MM:SS| vmx| I005: DiskHotRemoveAction: Device 'scsi0:3' was not found for hot removal!
...

The vCenter Server vpxd.log shows: 
...
YYYY-MM-DD HH:MM:SS info vpxd[45959] [Originator@6876 sub=Default opID=5c1c17db-01] [VpxLRO] -- ERROR lro-46543942 -- vm-45 -- vim.VirtualMachine.reconfigure: vim.fault.GenericVmConfigFault:
--> Result:
--> (vim.fault.GenericVmConfigFault) {
--> faultCause = (vmodl.MethodFault) null,
--> faultMessage = (vmodl.LocalizableMessage) [
--> (vmodl.LocalizableMessage) {
--> key = "msg.disk.hotadd.Failed",
--> arg = (vmodl.KeyAnyValue) [
--> (vmodl.KeyAnyValue) {
--> key = "1",
--> value = "scsi0:3"
--> }
--> ],
--> message = "Failed to add disk 'scsi0:3'."
--> },
--> (vmodl.LocalizableMessage) {
--> key = "msg.disk.hotadd.poweron.failed",
--> arg = (vmodl.KeyAnyValue) [
--> (vmodl.KeyAnyValue) {
--> key = "1",
--> value = "scsi0:3"
--> }
--> ],
--> message = "Failed to power on 'scsi0:3'. "
--> },
--> (vmodl.LocalizableMessage) {
--> key = "msg.disk.noBackEnd",
--> arg = (vmodl.KeyAnyValue) [
--> (vmodl.KeyAnyValue) {
--> key = "1",
--> value = "/vmfs/volumes/950b5e9a-13d5d4f2/vm-45-disk-key-2002.vmdk"
--> }
--> ],
--> message = "Cannot open the disk '/vmfs/volumes/950b5e9a-13d5d4f2/vm-45-disk-key-2002.vmdk' or one of the snapshot disks it depends on. "
--> },
--> (vmodl.LocalizableMessage) {
--> key = "msg.disklib.INVALIDDISK",
--> arg = <unset>,
--> message = "The file specified is not a virtual disk"
...

The Instance Access (IA) restore of the saveset completes successfully, but the VM startup or manually reconfiguring on another VM generates the same error.

Cause

There is an inconsistency in the backup descriptor files for the virtual disk (ex: CapacityInBytes, UsedBytes, UsedBlocks, and SectorCount).  In some instances, the inconsistency can occur when a virtual disk is expanded with the vmkfstools command-line utility.

Resolution

The vProxy 4.3.0-15 release includes code enhancements in the VM backup and FULLVM image-level restore for descriptor inconsistency scenario's. The backup enhancements ensure that new backups do not generate the failure during the FLR and IA restore. The FULLVM restore enhancements allow the restore of the previous backups that are taken with descriptor inconsistencies.

Install the latest NetWorker vProxy release to resolve the symptom. The latest vProxy release is available on the Dell NetWorker Support Download web page:

https://www.dell.com/support/home/en-us/product-support/product/networker/overview
NVP vProxy: How To Upgrade the NVP vProxy Appliance using nsrvproxy_mgmt
Article Properties
Article Number: 000197011
Article Type: Solution
Last Modified: 07 Nov 2025
Version:  3
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