Synology Azure Backup: How to Back Up to Azure

Synology Azure backup lets you copy data from a Synology NAS to Microsoft Azure Blob Storage, giving you an offsite copy that survives local drive failures, ransomware, and site-level disasters. You set it up through the built-in Cloud Sync or Hyper Backup package, enter your Azure storage account credentials, choose a folder or share, and the NAS pushes encrypted data to Azure on a schedule you define. This article explains the two main ways to do it, what each costs, common pitfalls, and how to decide which method fits your setup.

Why Back Up a Synology NAS to Azure

A NAS protects against a single drive dying, but it does not protect against the whole unit being stolen, flooded, or encrypted by ransomware. An offsite copy in Azure means your data exists in a separate physical location, managed by Microsoft’s data centers. Azure Blob Storage is a common target because it is cheap for infrequent access, supports versioning, and integrates with Synology’s built-in tools without extra software. Many home users and small businesses already have an Azure account for other services, so adding a backup bucket is a natural extension.

Two Ways: Cloud Sync vs. Hyper Backup

Synology offers two distinct tools, and people often confuse them. Cloud Sync is a real-time synchronization tool: it mirrors a local folder to Azure and keeps both sides in sync. If you delete a file locally, it deletes it in Azure (unless you enable versioning). Hyper Backup is a true backup tool: it creates a compressed, deduplicated archive with version history, so you can restore files from any point in time, and it protects against accidental deletions or ransomware because old versions are kept.

• Cloud Sync – best for sharing files across devices, accessing them from anywhere, or keeping a live copy. Not a backup in the strict sense.
• Hyper Backup – best for disaster recovery, versioned backups, and restoring a NAS after failure. This is what most people mean by “backup.”

How to Set Up Hyper Backup to Azure

Hyper Backup is included in Synology DSM and supports Azure Blob Storage as a destination. The setup takes about ten minutes if you have an Azure storage account ready.

1. Open Hyper Backup from the DSM main menu.
2. Click + and select Data backup task.
3. Choose Remote NAS device or Cloud service – select Microsoft Azure Blob Storage.
4. Enter your Azure storage account name and access key (found in the Azure portal under Storage account → Access keys).
5. Select the container you want to use, or create a new one.
6. Choose the local folders you want to back up.
7. Set a schedule (daily, weekly, etc.) and enable encryption with a strong password – this protects data at rest even if someone gains access to your Azure account.
8. Enable integrity check to verify backups periodically.

After the first backup, Hyper Backup keeps a local index and uploads only changed blocks, so subsequent backups are fast and use minimal bandwidth.

How to Set Up Cloud Sync to Azure

Cloud Sync is the simpler tool if you only need a live mirror of a folder. It works in one direction (upload) or two directions (sync).

1. Install Cloud Sync from Package Center if not already installed.
2. Open it and click +.
3. Select Microsoft Azure Blob Storage.
4. Enter your storage account name and access key.
5. Choose a container and a local folder.
6. Select sync direction: Upload local changes only (one-way) or Bidirectional sync.
7. Set a schedule or run continuously.

Cloud Sync does not compress or deduplicate data – it uploads the raw files. This means storage costs can be higher than Hyper Backup for the same data, but you get direct file access from Azure without needing Hyper Backup Explorer.

Costs and Storage Tiers

Azure charges for storage, operations (read/write), and data transfer. For backup, you typically want the Cool or Archive tier, which are cheaper than Hot but have minimum storage durations (30 days for Cool, 90 days for Archive). If you plan to restore frequently, Hot might be worth the extra cost. Data transfer out of Azure to the internet is charged per GB, but uploads are free. Hyper Backup’s deduplication can reduce storage by 20–50% for typical file shares, which directly lowers your bill.

Common Problems and How to Fix Them

• Authentication errors – Double-check the access key. Azure has two keys; either works. Make sure the key is for the correct storage account.
• Container not found – The container name must be lowercase, 3–63 characters, and contain only letters, numbers, and hyphens. Create it in the Azure portal first, or let Synology create it if the name is valid.
• Slow initial backup – The first backup uploads everything, so it can take days for large data. Enable network throttling in Hyper Backup to avoid saturating your internet. Consider seeding with a portable drive if you have many terabytes.
• Restore fails – Ensure you have the encryption password. Hyper Backup stores a local copy of the key, but if you lose the password, the backup is unrecoverable.
• Sync conflicts in Cloud Sync – If you edit the same file on both sides, Cloud Sync creates conflict copies. Use one-way upload if you only need a copy, not true sync.

Security and Encryption

By default, data sent to Azure is encrypted in transit via HTTPS, and Azure encrypts data at rest with Microsoft-managed keys. However, for sensitive data, enable Hyper Backup’s client-side encryption. This encrypts the backup before it leaves your NAS, so even if someone steals your Azure credentials, they cannot read the files. The encryption password is not stored anywhere – write it down and keep it safe. You can also enable Azure Blob versioning at the container level to protect against accidental deletion or ransomware overwriting your backups.

Alternatives to Azure

Synology supports other cloud providers natively: Amazon S3, Google Cloud Storage, Backblaze B2, and Wasabi. The setup is nearly identical. If you prefer no ongoing costs, you can back up to another Synology NAS at a friend’s house using Hyper Backup’s Remote NAS feature. For a simple offsite copy without cloud vendor lock-in, consider an external USB drive rotated offsite. Azure is a solid choice if you already use Microsoft services or need geo-redundancy (Azure’s LRS or GRS options).

Frequently Asked Questions

Is Cloud Sync a backup?

No. Cloud Sync mirrors changes in real time, so a ransomware attack that encrypts your local files will also encrypt the cloud copy. Hyper Backup is a true backup because it keeps previous versions, allowing you to roll back to a clean state.

Do I need a paid Azure subscription?

Yes, Azure Blob Storage is a paid service. You pay for storage and operations. There is no free tier for Blob Storage, but the first 5 GB is often covered by a free trial credit. Check the current pricing on Microsoft’s site.

Can I restore individual files from Hyper Backup?

Yes. In Hyper Backup, select the backup task, click Restore, and choose Restore specific files. You can browse the archive and select files or folders to restore to your NAS or download them to your computer.

How long does the first backup take?

It depends on your upload speed and data size. For example, 1 TB at 20 Mbps upload takes about 5 days continuously. You can speed it up by using a faster internet plan or by seeding the data via a different method, but Synology does not officially support offline seeding to Azure.

What happens if I delete a file locally after Cloud Sync uploads it?

If you are using one-way upload, the file remains in Azure. If you are using bidirectional sync, it will be deleted from Azure as well. Enable Azure Blob versioning or soft delete to keep a copy.

Can I back up multiple NAS units to one Azure account?

Yes, but use a separate container per NAS to avoid mixing data. Each Hyper Backup task can target a different container. Just ensure you have enough storage and that you keep access keys secure.

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