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  4. Features & Configuration

Understanding UniFi Drive Storage Pools and RAID Groups

UniFi Drive enhances flexibility and scalability by supporting multiple storage pools and RAID groups. This guide covers key concepts, setup instructions, and how to monitor your drives and storage status. For more information on the RAID options offered by UniFi, click here. 

  • Storage Pool: A logical container that manages one or more RAID groups. Each pool functions independently, allowing different drive types and RAID configurations.
  • RAID Group: A set of drives within a storage pool, configured to enhance redundancy and performance. Each storage pool can contain multiple RAID groups.

Note: If a storage pool contains multiple RAID groups, the user interface does not allow manual selection of a specific RAID group for data storage. Always promptly resolve any RAID group issues to prevent potential data loss. 

Creating Storage Pools and RAID Groups

To begin using UniFi Drive, you'll need to create at least one storage pool that contains one or more RAID groups. Each RAID group must meet the minimum drive requirement based on your selected RAID type to ensure optimal redundancy and performance. 

Navigate to Settings > Control Plane > Storage > Create Storage Pool. 

Requirements

  • When adding a second RAID group to a storage pool, each group must have at least two drives.
  • Use only HDDs or only SSDs within a single RAID group. Mixed drive types are not supported.
  • For RAID 10 (Advanced Performance), only one RAID group is allowed per storage pool.
  • While a storage pool is being created, formatted, or mounted, no other storage pools can be created or modified.

Expanding Storage Pool and RAID Group Capacity

To expand the capacity of a RAID group, add additional drives to its storage pool. This enhances both storage size and potential performance, depending on the RAID configuration.

Navigate to Settings > Control Plane > Storage > select a storage pool > select a RAID group > select a drive to add. 

Requirements

  • Only drives with Unassigned status can be added to a storage pool.
  • Expansion is only allowed when the system is idle (not syncing, repairing, or performing other storage operations).
  • Drive bay availability can limit your ability to expand RAID groups.
    • Example: On a UNAS Pro with 7 bays, if you create a RAID 6 storage pool with two RAID groups (one using 4 drives and the other 3 drives), you will fully occupy all available drive bays. Since no bays remain, you won't be able to expand the second RAID group later. Moreover, because RAID 6 requires at least 4 drives, the second group (with only 3 drives) will be automatically configured as RAID 5, which provides only single-drive redundancy.

Storage Pool Statuses

UniFi Drive displays different storage pool statuses depending on system activity, configuration changes, or hardware issues. Use the following guide to understand what each status means and when to take action.

Operational States (No Action Needed)

These statuses appear during normal operations such as creation, formatting, or expansion. The system will automatically transition to Fully Operational once the task is complete. If a status persists longer than expected, monitor the situation and take appropriate action.

  • Fully Operational: All drives are healthy and protected. No issues detected.
  • Syncing: Data is synchronizing after a new drive has been added to a RAID group.
  • Expanding: The storage pool is increasing in capacity with newly added drives.
  • Formatting: Drives are being initialized and prepared for use.
  • Mounting: The storage pool is loading, usually after the system has been restarted.
  • Updating: System changes (e.g., RAID group modification) are being applied.
  • Repairing: The system is rebuilding or correcting data using RAID redundancy.

Warning or Risk States (Action Recommended)

These statuses indicate reduced protection or reliability concerns. Prompt action is recommended to avoid service disruption or data loss.

  • At Risk: One or more drives are faulty. The storage pool is still operational, but with reduced protection. Replace the affected drives immediately.
  • No Data Protection Yet: The storage pool lacks redundancy. Add more drives to meet the minimum RAID requirements.
  • Removing: Storage pool removal is in progress. Ensure data is backed up or no longer needed.

Critical Failure States (Immediate Action Required)

These statuses indicate serious faults. Take action immediately to avoid permanent data loss.

  • Storage Failed: The system cannot access the drives. Data loss may have occurred. Replace the drives or recreate the storage pool.
  • File System Error: The file system is corrupted. Contact UniFi Support for recovery assistance.
  • Read Only: The storage pool is mounted in read-only mode due to RAID or file system issues. Back up data immediately, then recreate the pool.
  • Storage Cannot Setup: The storage pool could not be initialized due to hardware or configuration errors. Troubleshooting steps:
    1. Remove the storage pool.
    2. Set up the pool using a single drive.
    3. Add the remaining drives one by one.
    4. Replace any drive that fails to add.
    5. If the issue persists, submit a support ticket.

Detached or Inactive States

These statuses occur when drives are disconnected or moved between systems.

  • UniFi Storage Found: Drives were used with another UniFi Console. Choose an option to continue:
    • Restore data: Go to Control Plane > Console > Controls > Factory Reset and restore the data from your UI Account backups.
    • Remove storage pool: Reformat the drives to use the current console.
  • Storage Not Found: All drives in the storage pool have been removed. Reinsert the original drives to recover the pool.

Learn more about drive and storage health

FAQs

What is the best practice for organizing storage?

  • Separate personal and work data by creating two distinct storage pools.
  • Configure different RAID types in each pool to suit different needs:
    • For critical or sensitive data, use RAID 6 (Advanced Protection).
    • For general-purpose data, use RAID 5 (Basic Protection).

What is a legacy pool, and what are its limitations?

A legacy pool refers to a storage pool created before updating to UniFi OS 4.3 and Drive 3.0. These pools:

  • Can't contain multiple RAID groups.
  • Can't add new drives if the existing RAID group mixes HDDs and SSDs.
  • Can only use local hot spares within the same storage pool.
    • After updating to UniFi OS 4.3 and Drive 3.0, you can convert a local hot spare into a global hot spare from the drive's details panel.

How does encryption work for storage pools?

  • Each storage pool has its own encryption key.
  • Only one storage pool can be encrypted or decrypted at a time.
  • You can select specific drives in a storage pool to encrypt or decrypt.
  • Losing the encryption key will result in permanent loss of access to the data in that pool.

What should I know about backup and restore behavior?

  • All drives from all previously created pools must be reinserted to successfully restore the data and configurations on your UNAS.
  • Partial pool restoration is not supported.
  • See instructions for migrating and restoring data between UNAS. 

What happens if I restore from an older backup?

Restoring from a backup that was created before a new storage pool was added may cause that newer pool to become unreadable. This occurs because the system state from the backup doesn't include the configuration of the new pool.

Let’s say you perform the following steps:

  1. Create Storage Pool 1 (used for work files)
  2. Create Backup of Storage Pool 1 (saves the state of Pool 1 only)
  3. Create Storage Pool 2 (used for personal media)
  4. Restore Backup of Storage Pool 1

Pool 1 is restored as expected, but Pool 2 is not recognized. The system may show it as UniFi Storage Found, and its data will appear inaccessible in the user interface.

This is a known limitation. If you encounter this, contact UniFi Support for assistance.

What if only some drives from a storage pool are reinserted?

  1. The system may enter a Storage Not Found state.
  2. You'll see a warning and be prompted to either:
    • Reinsert all original drives
    • Or erase the missing pool configuration (irreversible)
  3. Once all original drives are reinserted, the pool will automatically recover and become fully functional.

Why can't I access shared or personal drives from an inaccessible storage pool?

Drives from an inaccessible storage pool will not appear in file access interfaces (e.g., All Files in UniFi Drive, SMB, UniFi Drive mobile app) until the pool is fully restored.

What happens if I reuse a name from an inaccessible storage pool?

If you create a new shared or personal drive with the same name as one from a missing pool, the system will prompt you to rename the new drive.

Do snapshots and backup tasks include inaccessible storage pools?

Yes. Snapshots and backup task limits still count entries from inaccessible pools until they are manually removed or restored.

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