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Managing Drives and Storage Pools in Unraid

Table of Contents
Difficulty Beginner
Time ~30 min
Stack
Unraid Storage

One of Unraid’s biggest advantages over traditional RAID is flexibility. You can upgrade parity, add drives, and reclaim old hardware without rebuilding the array from scratch or touching your data. This guide walks through a real-world upgrade scenario from start to finish.

Executive Summary
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Starting with a 5GB parity drive and three 5GB data drives, we will upgrade parity to a 10GB drive, reclaim the old parity drive as a data drive, and add a brand new 5GB data drive to the array. By the end we will have a 10GB parity drive protecting five 5GB data drives.

Prerequisites
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ComponentRequirement
Unraid ServerA running server with a started and parity-protected array
New DrivesPhysically installed and visible in Unraid’s Unassigned Devices section

Assumptions: This guide follows on from Installing and Configuring Unraid. Your array should already be started with at least one parity drive and one or more data drives before continuing.

Implementation
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Step 1: Confirm New Drives Are Detected
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Before making any changes, confirm that Unraid can see your new drives and that your array is healthy.

  1. Click the Main tab in the top navigation bar.
  2. Scroll down to the Unassigned Devices section. Your new drives should appear here with their size and model listed.
  3. Confirm the Array Operation section at the bottom shows Parity is valid. Never make drive assignment changes on a degraded array.

Unraid Main Tab with Unassigned Devices
The Main tab showing the current array with two new unassigned drives and a valid parity status. This is the starting point.

Step 2: Run a SMART Test on the New Drives
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Before adding any drive to the array, run a SMART test on it. SMART (Self-Monitoring, Analysis, and Reporting Technology) is a built-in health monitoring system that every modern hard drive uses to track its own condition. Running a test before adding a drive catches problems before your data depends on it.

  1. In the Unassigned Devices section, click on the name of your new drive to open its details page.
  2. Click the Self-Test tab at the top of the page.
  3. Click Start next to SMART short self-test and wait for it to complete. A short test takes 2 to 5 minutes and catches most common drive problems.

Unraid SMART Test
The SMART Self-Test page. The short test is the fastest way to check a drive before adding it to the array.

  1. Confirm the Last SMART test result shows Completed without error.

Unraid SMART Test Result
Completed without error means the drive passed its health check and is safe to add to the array.

  1. Repeat for the second new drive.

Note: A SMART extended self-test is more thorough but can take several hours on larger drives. For new drives, run the short test first and the extended test overnight before trusting the drive with important data.

Step 3: Upgrade Parity to the Larger Drive
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Unraid requires that the parity drive is always equal to or larger than the biggest data drive in the array. Since our new 10GB drive is larger than the existing 5GB parity, we need to promote it to parity before we can do anything else.

  1. Click the Main tab and scroll to the Array Operation section at the bottom.
  2. Click Stop.

Unraid Stop Array Button
Click Stop to take the array offline before making any drive assignment changes.

  1. Unraid will ask you to confirm. Click Proceed.

Unraid Stop Array Confirm
Confirm that you want to stop the array.

  1. Once the array is stopped, click the Parity slot dropdown and select the 10.7GB drive.

Unraid Array Stopped with Parity Dropdown
The array in a stopped state with the Parity slot dropdown available for reassignment.

  1. Unraid will warn you that all existing data on the new drive will be overwritten. This is expected as the drive needs to be written with new parity data.

Unraid Assign New Parity Overwrite Warning
The overwrite warning confirms the new 10.7GB drive is assigned to parity. The old 5.4GB parity drive moves to Unassigned Devices automatically.

  1. Click Start to restart the array. Unraid will begin a Parity Sync, rebuilding parity data onto the new 10.7GB drive.

Unraid Parity Sync Early
Parity sync in progress. The array is usable but performance will be reduced until the sync completes.

Note: Do not power off the server or make further drive changes while the sync is running. Cancelling a parity sync leaves the array unprotected.

  1. Wait for the sync to complete. The status will update to Parity is valid when done.

Unraid Parity Valid After Upgrade
Parity sync nearly complete at 97.5%. Once it reaches 100% the array is fully protected by the new drive.

Step 4: Add the Reclaimed and New Drives
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With parity upgraded, the old 5.4GB parity drive is now sitting in Unassigned Devices. We can add it to the array as a data drive along with the brand new 5.4GB drive.

  1. Stop the array again.
  2. The Slots dropdown controls how many disk slots are visible. Increase it to accommodate both new drives.

Unraid Increase Slots
Increasing the slot count reveals empty Disk 4 and Disk 5 slots ready for assignment.

  1. Click the Disk 4 dropdown and select the old parity drive (sdb).

Unraid Assign Reclaimed Drive
Assigning the old parity drive to Disk 4. Both the reclaimed drive and the new drive are available in the dropdown.

  1. Click the Disk 5 dropdown and select the new 5.4GB drive (sdg).

Unraid Assign New Data Drive
Assigning the brand new 5.4GB drive to Disk 5.

  1. Both drives will show the overwrite warning in red. This is expected for drives being added to the array for the first time.

Unraid Assign Drives Overwrite Warning
Both new drives show the overwrite warning. Unraid will clear and format them when the array starts.

Step 5: Format the New Drives
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With both drives assigned, start the array and format them so Unraid can use them for storage.

  1. Click Start. Unraid will begin a Disk-Clear operation on the new drives before formatting them.

Unraid Disk Clear in Progress
Disk-Clear in progress. Unraid is zeroing the drives before writing the file system. This ensures no old data interferes with parity calculations.

  1. Once Disk-Clear completes, Unraid will show both drives as Unmountable and present a Format button with a Yes, I want to do this checkbox.

Unraid Format Ready
The array is ready to format the unmountable drives. Check the box and click Format to proceed.

  1. Check the Yes, I want to do this box and click Format.
  2. Unraid will display a warning dialog explaining that all data on the drives will be erased. Click OK to confirm.

Unraid Format Warning Dialog
The format warning is a final safety gate. Clicking OK will write the XFS file system to both drives.

  1. Unraid will format both drives and run a final parity sync to extend protection to the new disks. Wait for it to complete.

Step 6: Confirm the Final Array
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Once formatting and parity sync are complete, your array should reflect the full expanded configuration.

Unraid Final Array
The completed array. One 10.7GB parity drive now protects five 5.4GB data drives with 25.8GB of total usable space and parity valid.

Lab Notes & Troubleshooting
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A new drive does not appear in Unassigned Devices. Power down the server and reseat the SATA data and power cables. If the drive still does not appear, test it in another machine to confirm it is functional.

SMART test returns “Completed without error” but the drive has high reallocated sector count. Check the Attributes tab on the drive details page. A high reallocated sector count (Attribute 5) on a new drive is a red flag even if the short test passes. Do not add the drive to the array.

Parity sync is running very slowly. This is normal for large drives. A 4TB drive can take 8 to 12 hours to sync at typical speeds. Do not interrupt the sync or power off the server while it is running.

The Stop button is greyed out during parity sync. Unraid disables the Stop button while a parity operation is running to protect the array. Wait for the sync to complete or use the Pause button if you need to temporarily halt it.

Array shows a red disk after a drive change. Stop the array, reassign the drive if it is still available, restart, and let parity rebuild before making further changes.

Summary
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You have successfully upgraded your parity drive to a larger one, reclaimed the old parity drive as usable storage, and added a brand new data drive to the array. The end result is more protected storage without losing a single byte of existing data. This is the standard Unraid upgrade path and one you will repeat as your storage needs grow over time.

Next Step: Managing Users and Permissions in Unraid

← Installing And Configuring Unraid Creating and Managing Shares on Unraid →
Disclaimer: Content on this site is provided as-is with no guarantees of accuracy, completeness, or fitness for any particular purpose. Always test in a safe, non-production environment before applying anything documented here to systems you rely on. I am not responsible for data loss, damage, or security issues resulting from following these guides. Software and services change over time and steps that worked when this was written may not work in the future.