Migrating and Seeding Veeam Backups to ReFS Storage

IMigrating to Veeam ReFS Volumes: Steps to Unlock Fast Cloning and Spaceless Fulls

To fully realize the benefits of Veeam’s integration with Windows Server 2016 ReFS, all full and incremental backups must be created on the new ReFS volume. Simply moving existing backups over won’t immediately enable fast cloning and spaceless fulls—additional steps are required.

For more details on the benefits of using Veeam with ReFS, be sure to check out our related post.

Update: Make sure to use 64K Block Size when formatting the Veeam repository volumes to avoid issues with 4K Block Size and ReFS. Read this post for more information.

Migrating Existing Backups to ReFS Volumes

The first key point to remember is that only new full and incremental backups created on ReFS will benefit from fast cloning and spaceless fulls. After moving your data to the new ReFS volume, performance and storage efficiency improvements won’t take effect until:

1. You create either an active or synthetic full backup.
2. Old incremental restore points are merged or deleted, and new ones are created on the new volume.

Dealing with Deduplicated Storage

If you’re migrating from a deduplicated storage, moving your backups to ReFS can result in rehydrated data, which could significantly increase the size of your backup files and overwhelm storage.

To mitigate this, you might want to:

• Keep older archived backups on the deduplicated storage or tape.
• Only migrate the most recent full backup (.vbk) and incrementals (.vib) to the new ReFS volume.

Planning for Storage Needs

Remember, ReFS benefits won’t be applied until both the most recent full and all incrementals are created on the ReFS volume. This means you’ll need storage for at least two full backups plus all incremental backups during the migration process.

We recommend scheduling a GFS (Grandfather-Father-Son) retention policy to create a full backup as soon as possible. This allows you to delete older full backups from the ReFS volume, freeing up space.

Once the synthetic full and new incrementals have been created on the ReFS storage, you can delete the oldest archive points from ReFS, and all subsequent backups will benefit from the ReFS filesystem improvements.

Seeding Offsite Backup Copy to ReFS Volumes

Seeding a backup to ReFS can help reduce initial WAN utilization, as it prevents the need for a full backup over the internet. However, even after seeding, all backups must be created on the ReFS volume to benefit from the new features.

Here’s a process that has worked well for us when seeding backups to ReFS (you’ll temporarily need storage for two full backups and two incremental restore points):

Steps to Seed Backups to ReFS:

1. Perform an initial full backup copy (seed backup) to an external drive at the primary location.
2. Ship the drive to the secondary location and import the .vbm and .vbk files into the target repository.
3. Rescan the repository from the primary site, adding the new backups to the Veeam configuration.
4. Edit the original job, point the target repository to the new repository at the secondary site, and use ‘Map Backup’ to select the newly imported backup.
5. Change the number of restore points to 2 (the minimum allowed).

Forcing a GFS Synthetic Full Backup:

1. Enable GFS retention and schedule a weekly backup to occur after the next incremental backup.
   • For example, if today is Wednesday and backups run nightly, allow the incremental backup to run Wednesday night and schedule the weekly backup for Thursday night.
2. After Wednesday’s incremental backup, the job will hit its retention limit of two restore points. On Thursday, the synthetic full backup will be created, generating the GFS restore point.

Once the GFS synthetic full is created, you can delete the archived full (..._W.vbk) to free up storage. (You can keep it, but archived fulls won’t benefit from ReFS spaceless fulls and will consume storage until deleted by retention.)

Afterward, you can change the retention settings of the backup job as needed, and any new backups will benefit from the ReFS filesystem.

By following these steps, you’ll ensure that your existing backup chains transition smoothly to ReFS while unlocking the powerful benefits of fast cloning and spaceless full backups.