Home --> Product --> Resource --> Resize RAID Partition --> Resize RAID 1 Partition

How to resize RAID 1 partition without destroying data?

The same with physical hard disk drive, the virtual drives on a RAID 1 array also runs out of space especially for system C: drive, but unlike single hard disk, hardware RAID 1 array is created by two drives via RAID controller. The key points raid users worry about includes:

  • Is it required breaking the raid 1 array before resizing partitions?
  • Is it safe to resize raid 1 partition without rebuilding the raid array?
  • What is the easiest way and how to resize raid1 partitions?

Relax, you can resize raid 1 drives within few steps and without starting over. However, to better understand how to resize raid partitions, I have to explain more about raid 1 array.

What is hardware RAID 1

RAID (redundant array of independent disks) is a storage technology that combines multiple disk drive components into a logical unit. Data is distributed across the drives in one of several ways called "RAID levels", depending on what level of redundancy and performance is required.

RAID 1 creates an exact copy (or mirror) of a set of data on two disks. A classic RAID 1 mirrored pair contains two disks, which increases reliability geometrically over a single disk. Since each member contains a complete copy of the data, and can be addressed independently, ordinary wear-and-tear reliability is raised by the power of the number of self-contained copies.

Raid 1 array

Single hard disk VS RAID 1 array

In this article, we are talking about resizing raid 1 partition, so just ignore raid 1 benefits, but we should know how raid 1 array works. As we know, RAID 1 creates exact copy on two disks. If you build a raid 1 array with 2 120GB disks, you get a virtual disk 120GB in disk management.

Disk management

In my computer, Disk 0 (raid 1) is created via 2 80GB hard disk and there are 3 virtual drives on this disk (raid array).

Though data read and write on raid 1 array is controlled by the independent CPU of the raid controller, Operating System doesn't know about this and treats the raid array with a physical hard disk. In fact, there is also no difference resizing a physical disk partition or a raid virtual drive. As long as there is free space in other drives on the same raid 1 array, you can shrink and extend any partitions. In this situation, the disk space issue can be solved easily.

How to resize raid 1 virtual partitions

Step1, launch partition magic server software and you'll see the disk partitions (both physical and raid virtual), the layout is the same with disk management above.

Main window

System C: drive is 20GB, I want to increase its partition size by taking free space from other data drive.

Step2, right click drive G: (or D:) and select "Allocate Free Space".

Select feature

In this pop-up window, specify how many free space to rob from drive G: and select C: as the target partition.

Add space to c

Step3, click OK and back to main window, press "Apply" button on top left to proceed.

Apply to proceed

Within several minutes to half an hour (depends on how many files in this partition to move), partition resizing complete, check again in Disk Management, C drive space increased to 34.12GB.

Partition resized

As I said above, it is easy to extend c drive when there is free space in other partition on the same disk (raid array). If your scenario is the same with mine, download the demo or purchase full version and begin to solve your problem, otherwise, please continue reading.

More complicated issue on raid 1

As RAID 1 "waste" the capacity of a hard disk, to save cost, some administrators create raid 1 for Operating System with 2 small disks, use other disks or raid array (such as raid5) for data. In this condition, there is only partition C on this raid 1, so you cannot shrink other drives to extend C directly, however, it is still possible to extend C drive without data loss.

Unlike software raid 1 (dynamic Mirrorred Volume), you cannot increase hardware raid 1 capacity by breaking the array, replace with larger disk and rebuild array one by one. To increase c drive space, follow the steps below:

  • 1. Copy your raid 1 to another hard disk (Disk 3) with the build-in "Disk Copy Wizard" feature.
  • 2. Replace original raid 1 disks with other 2 large disks, create RAID 1 array from BIOS or via your raid application.
  • 3. Copy Disk 3 to the new raid 1. (you can extend partition when copying)

Copy extend raid1

If you have enough slots to connect 4 hard disks, you can directly copy old raid array to the new raid 1. (remember to change partition size during copy)

This page seems very long, but in fact it is easy to resize raid 1 partitions, open disk management to find out the partition layout and then follow the steps that is related to your scenario.

Home || Products || Download || Buy Now || Tutorials || Screenshot || Support

Copyright © 2008-2012 partition-resize.com ALL RIGHTS RESERVED.

Partition Magic ® is a registered trademark of Symantec Corporation.