Veeam Backup and Replication Error: Failed to open VDDK Error Message

PROBLEM:

   Certain VMs are unable to being backed up due to error message Error: Failed to open VDDK disk datstore_name_VM_Name.vmdk] ( is read-only mode - [true] ) Failed to open virtual disk disk datstore_name_VM_Name.vmdk (flags: 4) Logon attempt with parameters [VC/ESX: [vcenter_server];Port: 443;Login: [account_name];VMX Spec: [moref=vm-56235];Snapshot mor: [snapshot-68079];Transports: [nbd];Read Only: [true]] failed because of the following errors: Failed to open disk for read. Failed to upload disk.

CAUSE:

This issue is related to connection between Backup Proxy and ESXi Host via Management Agent.

RESOLUTION:

Identify the VMs being affected, then see if they are all belong to the same host, then proceed to the following steps:

1. Log in to SSH or Local console as root on the host in question.

2. Run these commands:

     /etc/init.d/hostd restart
    /etc/init.d/vpxa restart

3. Run this command to verify if hostd is running:

    /etc/init.d/hostd status

4. If the ESXi Host is manage by a vCenter Server, run the following command to verify if the vpxa  is running:

    /etc/init.d/vpxa status

5. Re-Try the Backup Job.

    If the problem persist, ensure that the account you are using to run the job have full access to download files on the datastore by login in to vCenter with those credentials, then proceed to explorer the content on the datastore were the VMs affected resides, then open the VM folder and identify the file on the message. Try to download the file in question, if it fail with Access Denied or not have permissions, then the issue is related to permissions therefore, provide Administrator Role to the account on vCenter. Also, make sure you are using the right Transport Mode for your proxy or proxies, please refer to the Veeam Backup & Replication Documentation for more information pertaining Proxies and Transport Mode.


Hope this helps!