Resize/Extend RAID Partition in Windows Server 2016/2019/2022

by John, Updated on: July 6, 2026

Many servers are built with hardware RAID arrays. For example, RAID 1 is typically used for the operating system, while RAID 5 or 10 is used for data storage. Just like a single physical disk, the system partition (C: drive) on a RAID array can also run out of space. To solve this problem quickly and easily, it is highly recommended to resize the RAID partition with a safe tool. Nobody likes to recreate partitions and restore everything from a backup. This article explains how to resize and extend a RAID partition in Windows Server 2016/2019/2022 without losing data.

Extend raid partition

How to Resize RAID Partition in Windows Server Without Third-Party Software

The Operating System and NIUBI Partition Editor treat a physical hard disk and a hardware RAID array exactly the same. In most cases, you can resize a RAID partition in Windows Server 2016/2019/2022 just as you would a physical disk partition, regardless of the RAID type or the brand of the RAID controller.

What you should consider is whether there is free space in any partition on the same RAID array. "The same array" refers to Disk 0, 1, etc., as shown in Windows Disk Management or NIUBI Partition Editor. For most servers, there is free space in one of the virtual partitions on the RAID. In that case, you can shrink it to extend another partition that is getting full. If there is no other virtual partition, or if the entire RAID array is full, the process is more complex, which is discussed in the last section.

When there is free space on the same RAID array, you may try the native Disk Management utility in Server 2016/2019/2022. It has "Shrink Volume" and "Extend Volume" functions to help resize NTFS partitions without losing data. However, Disk Management is not the best tool because it has several restrictions.

The major disadvantage of Disk Management is that it can only resize NTFS partitions; FAT32 and other types of partitions are not supported. Furthermore, even for NTFS partitions, Disk Management can only shrink them to create a new volume. If you want to extend a partition by shrinking another one, Disk Management cannot help you. To extend or resize a RAID partition in Server 2016/2019/2022, you are better off running safe partition software.

How to Resize/Extend RAID Partition With Safe Partition Software

On most servers, there is plenty of free space in at least one of the virtual partitions on the RAID array. You can shrink it to free up unallocated space and then add it to the other RAID partition that you want to expand. Open Windows Disk Management or NIUBI Partition Editor to see if the partitions you want to shrink and extend are on the same RAID array.

How to Resize/Extend RAID Partition in Windows Server 2016/2019/2022:

  1. Download NIUBI Partition Editor, right-click an NTFS or FAT32 partition, and select "Resize/Move Volume". Drag either border towards the other in the pop-up window to shrink this partition. If you drag the left border towards the right or enter an amount in the "Unallocated space before" box, unallocated space will be created on the left side of this partition.
  2. If you want to create a new partition on this RAID array, right-click the unallocated space and select "Create Volume". If you want to shrink the D drive to extend the C drive, ensure you make the unallocated space on the left when shrinking D. Then, right-click the C: drive and select "Resize/Move Volume" again; drag the right border towards the right in the pop-up window to combine this contiguous unallocated space.
  3. Click Apply on the top left to execute the changes. (All operations prior to this step only work in virtual mode.)

Video guide

  • If you want to shrink a non-adjacent partition (like E:) to extend the C drive, there is an additional step to move the D drive to the right before adding the unallocated space to the C drive.
  • Whether you use RAID 1, 5, 6, or 10, do not break the RAID array or perform any operations on the RAID controller.

After resizing a RAID partition in Windows Server 2016/2019/2022, the operating system, programs, and everything else (except the partition size) will remain exactly the same as before.

How to Expand RAID Array Without Losing Data

If there is no available free space on the same RAID array, what should you do? The solution depends on how your RAID is configured.

For hardware RAID 1, on many older or basic controllers, you cannot increase the size of the RAID array simply by replacing the disks with larger ones one by one and rebuilding the array. If you do this, the RAID 1 might keep its original size, and the additional space won't be shown by Disk Management or NIUBI Partition Editor (it can only be used to create another separate array). However, if your controller supports expanding the LUN, you can expand it directly.

Steps to Extend RAID 1 in Windows Server 2016/2019/2022 With Larger Disks:

  1. Build a new RAID 1 with 2 larger disks.
  2. Right-click the front of the original RAID 1 and select "Clone Disk".
  3. Select the new RAID 1 and click Next in the subsequent window.
  4. Edit the size and location of the partitions in the new RAID 1, starting from the last partition and working backward one by one.
  5. Check the option to shut down the server after clicking Apply to execute the changes.

Video guide

  • After the copy is complete, change the BIOS settings to boot from the new RAID 1.
  • If you cannot attach two RAID arrays at the same time, you can clone the old RAID 1 to a physical disk, and then clone that disk to the new RAID.
  • If your modern RAID controller supports expanding RAID 1 without losing data, you can replace the disks one by one, let it rebuild, expand the array capacity in the RAID BIOS/utility, and then extend the partitions with the newly available unallocated space.

For hardware RAID 5, you can increase its capacity easily. However, before doing this, you should check the brand and model of your RAID controller to confirm it has the ability to expand RAID 5 capacity without losing data. If so, follow the steps to extend a RAID 5 partition in Windows Server 2016/2019/2022:

  1. Replace the drives with larger disks or add more disks of the same size to expand the array via your RAID controller.
  2. The additional space will be shown as "unallocated" at the end of the original RAID array in Windows Disk Management. You can then combine this unallocated space into the partition(s) you want to expand.

Unlike many other tools, NIUBI Partition Editor is much safer and faster because of its Virtual Mode, Cancel-at-will, unique 1-Second Rollback technologies, and advanced file-moving algorithm. Besides shrinking, extending, and copying disk partitions, it helps you move, merge, convert, defragment, hide, optimize, and wipe partitions, as well as scan for bad sectors and much more.

Download

➤