How to change partition size in Windows Server 2012

by Jacob, Updated on: December 18, 2020

This article introduces how to adjust partition size on Windows Server 2012 R2 without losing data. 2 ways to change Server 2012 partition size with native and third party tools.

Partitions are allocated while installing Operating System or by OEM manufacturer. Many people need to change partition size after running the server for a period of time. The typical example is that C drive is getting full, so they want to increase C drive space. Some other people want to shrink a large partition to create more volumes. Is it possible to change partition size in Windows Server 2012 without losing data? The answer is yes, but you'd better make a backup in advance, because there's potential system damage and data loss risk while resizing partitions. In this article, I'll introduce how to adjust partition size with Server 2012 native Disk Management and safest partition software.

1. Change partition size with Windows Server 2012 Disk Management

From Windows Server 2008, Microsoft added Shrink and Extend Volume functions in built-in Disk Management to help change volume size without losing data (not 100%). However, both functions have many shortages. Windows Server 2012 inherited the same functions without any improvement, so you'll encounter many issue while adjusting Server 2012 partition size with this native tool.

How to decrease partition size with Server 2012 Disk Management:

  1. Press Windows and X on keyboard and then select Disk Management in the list.
  2. Right click the partition to decrease and select Shrink Volume.
  3. Enter an amount of space and click Shrink. (If you don't enter an amount, maximum available free space is used by default.)

Shortages of Shrink Volume function:

  1. It can only shrink NTFS partition, other partitions are not supported.
  2. It can only shrink partition towards left and make Unallocated space on the right.
  3. It cannot shrink partition beyond the point where unmovable files are located.

Shrink partition

How to increase partition size with Server 2012 Disk Management:

  1. Back up or transfer files in drive D (for example).
  2. Right click it and select Delete Volume.
  3. Right click the left contiguous partition (C:) and select Extend Volume.
  4. Click Next till Finish in the pop-up Extend Volume Wizard window.

Shortages of Extend Volume function:

  1. It can only extend NTFS partition.
  2. It can only extend partition with adjacent Unallocated space on the right.
  3. On MBR disk, Unallocated space deleted from Primary partition can't be extended to any Logical drive, Free space deleted from Logical drive can't be extended to any Primary partition.

Extend volume disabled

If you want to extend a partition by shrinking another one, it is impossible with Disk Management. As you see in the screenshot, after shrinking D: drive, Unallocated space is non-adjacent to C, E drive is on the right side. Therefore, Extend Volume greyed out for both partitions.

Extend volume disabled

2. Adjust partition size in Windows Server 2012 with NIUBI Partition Editor

Comparing with Disk Management, third party partitioning software have many advantages such as:

There are many partition software in the market, the GUI and functions are similar. Few people know the importance of data protection. As I said in the beginning, there's potential system damage and data loss risk while resizing partition. You'd better back up first and run safe partition software.

Better than other software, NIUBI Partition Editor has innovative technologies to protect your system and data:

  1. Virtual mode - avoid incorrect operations by listing all as pending for preview, real disk partitions won't be modified until click Apply to confirm.
  2. Cancel-at-well - if you applied any incorrect operations, you can cancel the ongoing operations without losing data.
  3. 1 Second Rollback - if anything goes wrong while changing partition size, it automatically reverts server to original status in a flash.

Download NIUBI Partition Editor and you'll see all disk partitions with graphical structure on the right, available operations to selected disk or partition are listed on the left and by right clicking. In my test server, there are drive C, D, E and a system reserved partition in Disk 0. Original drive D: is 70GB and C: is 40GB.

NPE Server

How to change partition size in Windows Server 2012 R2 with NIUBI:

Right click a partition such as D: and select "Resize/Move Volume" to shrink it.

If you drag left border towards right, or enter an amount in the box of Unallocated space before:

Shrink D rightwards

Then Unallocated space is made on the left side of D.

Unallocated produced

If you drag right border towards left, or enter an amount in the box of Unallocated space after:

Shrink D leftwards

Then Unallocated space is made on the right side of D.

Unallocated generated

Right click C: or E: drive and run "Resize/Move Volume" again to expand it.

To extend C drive, drag right border towards right in the pop-up window.

Drag to extend

Then Unallocated space is extended into C: drive.

C drive extended

To extend E drive, drag left border towards left in the pop-up window.

Drag to extend

Then Unallocated space is extended into E: drive.

Drive E extended

Click Apply on top left to confirm and execute.

Watch the video how to adjust partition size on Windows Server 2012 without data loss:

Video guide

No partitioning software can extend a volume by taking free space from another separate disk, so if there is no available free space on a disk, you need to clone this disk to a larger one and extend partition with extra space. Watch the video

3. Change virtual partition size for RAID array, VMware, Hyper-V

If you want to adjust RAID partition size in Windows Server 2012 (r2), do not break array or any operations to raid controller, just follow steps above. To Operating System and NIUBI, there's no difference if you use physical hard disk or hardware raid array.

If you want to change size of virtual partition for Windows 2012 server in VMware or Hyper-V, firstly, check if there's available free space on the same virtual disk. If yes, install NIUBI Partition Editor to the virtual server and follow the steps above. If there's no available free space on the same disk, you can expand the virtual disk without losing data, and then extend partition with additional disk space.

Besides change partition size in Windows Server 2012, 2016, 2019, 2003, 2008, NIUBI Partition Editor helps do many other disk and partition management operations.

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