Frequently asked questions about snapshots

There are several possible reasons you are unable to take snapshots:

• You are using a legacy NAS model. Legacy models do not support snapshots.
• You are using one of the NAS models that do not support snapshots.
• You have not created a storage pool yet. You can only take snapshots of storage objects inside a storage pool.

If a storage pool was created on a NAS that did not support snapshots, the storage pool will not be able to support snapshots even if you migrate it to a new NAS that does support snapshots. You will need to back up the data to an external drive, create a new storage pool on a new NAS that supports snapshots, and transfer the data into the new pool. For details, see this article.

Thin-provisioned storage objects such as thin volumes (QTS), thin shared folders (QuTS hero), and thin LUNs (QTS and QuTS hero) are well-suited for snapshots. A thin object does not have preallocated space and their snapshots are stored in the parent storage pool, so the snapshots will not take up space in the thin object.

The number of snapshots you can take depends on the CPU model and installed memory. For details, go here.

Snapshots in Storage & Snapshots and in Virtualization Station are all point-in-time records of data. However, snapshots in Storage & Snapshots record the data of a volume (QTS), shared folder (QuTS hero), or LUN (QTS and QuTS hero), whereas snapshots in Virtualization Station preserve the state and data of a virtual machine.

Pool guaranteed snapshot space is storage pool space that is reserved for storing snapshots. Enabling pool guaranteed snapshot space ensures that a certain number of snapshots are retained. Without pool guaranteed snapshot space, the snapshots are stored directly in the storage pool and may be automatically removed when the system needs to free up space for other purposes, such as thin provisioning.

No, snapshots are not independent backup copies of files. Snapshots are records of metadata changes in the storage pool, and therefore are dependent on the storage pool they are stored in. You cannot move snapshots to a different location.

If you take snapshots of a thick storage object (such as a thick volume in QTS, thick shared folder in QuTS hero, or thick LUN), new data written to the empty space of the storage object increases the snapshot used space by the same size as the new data. You must monitor the pool free space and recycle older snapshots periodically to avoid running out of pool space. For this reason, we recommend thin storage objects if you want to take snapshots.

Thin storage objects (such as thin volumes in QTS, thin shared folders in QuTS hero, and thin LUNs) take up space in a storage pool on an on-demand basis, which means they only use up more space in the storage pool as data is written to the storage object. Storage pool oversubscription occurs when a thin storage object and its snapshots require more space than the storage pool can provide. For details and solutions, see here.

1. Open Storage & Snapshots. 
2. Go to Storage > Storage/Snapshots.
3. Identify a volume (QTS), shared folder (QuTS hero), or LUN (QTS and QuTS hero) that has a snapshot icon under the Snapshot column.
4. Click the snapshot icon.
   The Snapshot Manager window opens. 
5. Click Schedule Snapshots.
   The Snapshot Settings window opens.
6. Disable the Enable schedule toggle switch.

Yes, you can configure the system to automatically stop taking snapshots when it has taken the maximum number of snapshots. 

1. Open Storage & Snapshots.
2. Go to Global Settings > Snapshots > When the number of snapshots reaches maximum. 
3. Select Stop taking snapshots. 
4. Click Apply.

When the "Enable smart snapshot" setting is enabled (in Snapshot Manager > Snapshot Settings > Schedule Snapshot), the system only takes a scheduled snapshot if data has been modified since the last snapshot was taken. 

Although you may not have directly modified the data, the system may still modify data blocks in the background for storage optimization purposes. Because snapshots include information on data blocks, the system still takes a scheduled snapshot if it detects changes in the data blocks, even though from the user's point of view there is no change in the actual data.

When you change the name of a shared folder, the physical path of the shared folder remains unchanged in the system. That is why the old name still appears in the snapshots no matter how many times you change the shared folder's name. 

To make snapshots record the new name, create a new shared folder with the desired name, move the data from the old shared folder to the new shared folder, and start taking snapshots of the new shared folder. For details, see this article.

There are two kinds of snapshot folders you can enable for access in File Station: a root "Snapshot" folder for authorized users and a "@Recently-Snapshot" folder in shared folders.

1. Log in to your NAS as an administrator.
2. Open Storage & Snapshots.
3. Go to Global Settings > Snapshots > Snapshot Access in File Station.
4. Optional: Enable Root snapshot folder (for authorized users).
   
   Note

   This setting enables the root folder "Snapshot" for administrators and users with the System Management role to manage all snapshots on the NAS.
5. Optional: Enable Snapshot folder in each shared folder.
   
   Note

   This setting enables individual folders named "@Recently-Snapshot" in each shared folder. The "@Recently-Snapshot" folder allows users to view snapshots in the shared folder when connecting via SMB/CIFS or AFP.
6. Click Apply.

No. "@Recently-Snapshot" folders are read-only. Snapshots are point-in-time records that cannot be edited or moved.

To see snapshots in a NAS shared folder in Windows Previous Versions—and therefore be able to restore files from the snapshots—ensure that all four of the following settings are enabled on the NAS: 

• Storage & Snapshots > Global Settings > Snapshots > Snapshot Access in File Station > Snapshot folder in each shared folder
• Control Panel > Privilege > Shared Folders > Shared Folder > Edit Properties > Enable Windows Previous Versions
• Control Panel > Network & File Services > Win/Mac/NFS/WebDAV > Microsoft Networking > Advanced Options > Allow symbolic links within a shared folder
• Control Panel > Network & File Services > Win/Mac/NFS/WebDAV > Microsoft Networking > Advanced Options > Allow symbolic links between different shared folders

For details, go here.

You can revert an existing volume (QTS), shared folder (QuTS hero), or LUN (QTS and QuTS hero) to a former state as recorded in a snapshot. For detailed instructions, see the relevant topics in the following user guides (please copy and paste a topic title into the search field to locate the topic in the user guide).

• QTS User Guide
  • Reverting a volume
  • Reverting a volume using a remote snapshot
  • Reverting a LUN
  • Reverting a LUN using a remote snapshot
• QuTS hero User Guide
  • Reverting a shared folder
  • Reverting a shared folder using a remote snapshot
  • Reverting a LUN
  • Reverting a LUN using a remote snapshot

To address the possibility of a user’s account ID changing over time, and to maintain information security and a stable correspondence between folders and permissions, QNAP snapshots do not store and therefore cannot restore the permission settings of shared folders. For details, see here.

System and app settings are saved on the system rather than in the system volume or any volume containing apps, so these settings will not be restored when reverting a volume using a snapshot.

In QTS, encrypted shared folders do not support snapshots. Although you can take a snapshot of a volume containing encrypted shared folders and later restore the volume with the encrypted shared folders intact, you cannot individually restore an encrypted shared folder from a snapshot. Encrypted shared folders in a snapshot also do not appear in the "@Recently-Snapshot" folder.