We have snapshot backups of fileshares but want to delete the fileshares without deleting backups.

Hi @Andrew Norman Thank you for explaining your requirement. We understand that you would like to delete the active Azure file share to reduce source storage costs while retaining the existing backup data for a future restore.

With snapshot-based Azure Files backup, the recovery points are stored as share snapshots associated with the source file share. Azure Files does not support permanently deleting the base file share while retaining its share snapshots. Therefore, if the file share is permanently deleted, its snapshot-only recovery points cannot be retained for future recovery.

To maintain a backup copy that is independent of the source file share, we recommend evaluating the Vault-Standard backup tier. Vault-Standard transfers backup data to the Recovery Services vault and provides offsite protection without a hard dependency on the continued availability of the source data. Before deleting the source file share, please complete the following validations:

1. Confirm that the file share protocol, storage account type, region, and configuration support Vault-Standard by reviewing the support matrix.
2. Change the backup policy from Snapshot to Vault-Standard, or configure a Vault-Standard policy as applicable.
3. Run an on-demand backup and verify that the backup job completes successfully.
4. Confirm that a Vault-Standard recovery point is available. Please note that changing the tier does not convert previously created snapshot-only recovery points into vaulted recovery points. Existing snapshots remain under their current retention, while future backups are transferred to the vault.
5. Perform a full-share test restore from the vaulted recovery point to an alternate file share and validate the restored data. For a Vault-Standard restore, the target file share must have at least 20 percent more free space than the source data being restored.
6. Review all dependencies, including application access, mount points, Azure File Sync, identities, networking, private endpoints, and automation scripts.
7. If backup protection must be stopped, select Retain Backup Data. Do not select Delete Backup Data, because that operation deletes all recovery points associated with the file share.
8. After the vaulted backup and test restore have been successfully validated, your authorized administrator can decide whether to delete the original file share.

Please also note that retained vaulted backup data may continue to incur Azure Backup protected-instance and backup-storage charges.

At this stage, the above provides the recommended resolution path. We suggest considering the requirement completed only after a Vault-Standard recovery point has been created successfully and a full-share restore to an alternate location has been validated.

Please refer the microsoft documentation for more details:

• Azure Files backup support matrix
• Back up Azure Files in the Azure portal
• Manage Azure Files backups
• Use share snapshots with Azure Files
• Frequently asked questions about backing up Azure Files

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You cannot delete an Azure file share while keeping its snapshots intact. An Azure Files share snapshot are not full fledged backups - they cannot outlive its base share, so deleting the share also deletes all associated snapshots. Azure Backup can also place locks and leases on the storage account and snapshots to maintain data consistency, which can prevent independent deletion.

Because Azure file share snapshots are incremental, retaining snapshots while deleting the base files would also not necessarily eliminate the storage costs associated with blocks still referenced by those snapshots.

If you choose Stop Protection and Retain Data in Azure Backup, this stops future backup jobs but does not allow you to delete the live file share while retaining its existing snapshots for later restores. The snapshots remain dependent on the underlying file share.

If your goal is to reduce storage costs while retaining the data, alternatives include copying the required data to another location with AzCopy before deleting the share, or reducing the Azure Backup retention period so that older recovery points expire sooner.

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hth

Marcin