Veeam: How to fix Broken backup chain < ProVirtualzone

This article will explain How to fix Broken backup chain in Veeam Backup & Replication.

A Broken Backup Chain is when you have a full Backup(.vbk) and several (can be 2 or more) incremental(.vib) that were deleted or corrupted. Mainly if you are not using “Reverse Incremental.” Increments are always injected in the last backup to create a full backup. With this option is more difficult to have a Broken Backup Chain.

Examples:

Note: “Reverse Incremental” is always a slow backup compared with “Incremental.” Since the last backup will always be a full backup and all incremental will be injected in the last backup.

I will discuss in this article when you try to restore a VM with a Backup that has a broken chain, you get an error: “Backup files are unavailable.”

Restore

Check the restore points and restore.

As you can see in the next screenshot, this VM had four restore points. You can now choose one of the restore points to restore the VM.

When you try to restore the VM, you get a backup with a broken chain and get the error: “Backup files are unavailable.”

Even when you get this error, the VM restore continues and finishes with the next image.

When checking the last line in the restore log, the incremental .vib file doesn’t exist.

The VM was created in the vCenter, but you cannot power it on, and there is no Virtual Disk.

Somehow this .vib file disappears from the Repository. This can only happen if there are issues with your Storage Repository, or you put one Repository Offline in maintenance mode, and some files will be unavailable, or someone deleted the files manually in the wrong sequence.

Even if you choose a different restore point or even the full restore point, you get the same error. Since the chain in this backup is broken, so cannot restore the VM.

Next is to check the Backup Repository and check if any restore points are not in the chain and if you have a Broken Chain Backup, fix it.

Check Backup Repository.
Go to Backups, then Disk, and select the Job that you are trying to restore.
Right-click and select Properties.

As you can check in the next image lot of Incremental restore points are not available. The only available is the Full Backup.

Upon investigating the Backup Chain(full backup and its incremental) is official that you have a Broken Backup Chain and needs to be fixed.

Note: Double-check other VMs to confirm that all have the same problem.

Fix Backup Chain

To fix this Broken Backup Chain, you need to select one of the broken/miss files and choose to Forget or to Delete to miss incremental files.

Forget — you can remove records about missing restore points from the configuration database. Veeam Backup & Replication will “forget” these restore points and not display them in the console. The backup files will remain on disk.
Delete — you can remove records about missing restore points from the configuration database and delete backup files from the disk.

There is also an option to perform this task only in the select Job/Restore Point or do for all for the Forget and Delete options.

To remove only the selected restore point and restore points that depend on it (a part of the backup chain starting from this restore point), select This and dependent backups.
To remove all restore points from the unavailable extent, select All unavailable backups.

For this particular case, I choose to option Forget and with the select All unavailable backups.

Why Forget option: I choose this option because I don’t know what happens to the missing incremental files and would not like to lose any VMs backup(when using the delete option). For now, you will fix the broken chain; then, you can troubleshoot what happened to the missing files. With this option, Backups will only be removed from Backup Inventory, not psychically.

If you find the missing files or see that the files are just miss-located(maybe in a different Repository that was set to maintenance mode), you can then import all Backup Chains to the Backup Inventory.

You can use this option just for the safe side and if you plan to try to recover the missing files.

Just confirm and let Veeam remove all corrupted restore points and fix the Backup Chain.

Note: Depending on your system and backup sizes, this procedure can take a while.

After Veeam removes all corrupted files, the only available restore point was the initial Full Backup. So it means that all incremental were corrupt, or files were deleted (for example, 2 and 3 from our Incremental initial image).

As you can check in the next image, all VMs have only one restore point available.

Note: It could even happen if you have new VMs backup in those corrupted incremental will no longer be available(in this example, had 20 VMs that were not available anymore). So, no backups for those VMs.