Convert LV or MD RAID1/0 to RAID5: Data-Safe Methods

In this tutorial, we walk you through the step-by-step process of converting LV or MD RAID1/0 configurations into RAID5 seamlessly (on Linux, with mdadm or LVM). From understanding the prerequisites to executing the conversion safely, we provide practical tips and expert guidance to ensure a smooth transition while preserving your valuable data intact. Whether you’re a sysadmin or a tech enthusiast, this article equips you with the knowledge and tools to upgrade your RAID setup with confidence.

Convert LV or MD RAID1/0 to RAID5: Data-Safe Methods

RAID 0 disk arrays are known for relatively high data access time, and that’s why people choose to use them primarily because of the considerable boost in the speed of read and write operations. However, their reliability and fault-tolerance leave much to be desired. Even if one of the drives is out of order, all the data in such a disk array is going to be lost. Recovering the information from this array type is quite a challenge, but even then, all the data you may be able to extract will certainly be damaged. In fact, this type is not much of a disk array because it offers no redundancy at all.

Go to view
🐧 How to Convert LV or MD RAID 1 and 0 into RAID 5 Without Losing Data 🐧

🐧 How to Convert LV or MD RAID 1 and 0 into RAID 5 Without Losing Data 🐧

On the contrary, RAID 1 is a very reliable and fault-tolerant solution, as all the data is duplicated to the other disk, creating a mirrored copy of the information on the other drive. Still, this approach affects the read and write speeds of the whole array, so it appears to be slower in accessing the data, if compared with RAID 0 systems.

If you have a spare drive, you can upgrade the existing RAID 1 array to RAID 5. This way, you will enjoy better reliability than RAID 0 could offer, and feel an impressive read/write speed boost in comparison with RAID 1. In the end, you get a RAID 5 system, which is both reliable, fault-tolerant and powerful enough to process your data faster than before.

How to convert RAID 1 (mirroring) into RAID 5 (parity)

All right, we’ve got a software md_RAID1 system created on a Linux operating system. This array consists of two drives.

A RAID 1 system made of two drives

We need to convert it into RAID 5 and then add one more drive, and while doing that we have to make sure that all the data from the disk array doesn’t disappear. There are several files there: photos, videos, documents, and so on.

Files stored on the disk array

Before you start the conversion, it is recommended to back up important information because if you make a mistake while typing commands, important data can be erased.

Open the terminal, and run this command to make sure that all the operations are performed with superuser rights:

sudo -i

and type the password.

Accessing root privileges

If the disk array is mounted, you need to unmount it with this command:

umount /dev/md0


umount /mnt

Unmount the storage

If the operating system tells you the target is busy, try to force this action:

umount -f /dev/md0

Forced unmount in Linux

After that, you have to stop your RAID 1 system, with the following command:

mdadm --stop /dev/md0

(whether it is md0 or another name depends on the path, which needs to be checked)

where md0 is the identifier for your RAID system.

Stopping the array

Of course, you can’t stop it if this is the RAID system you boot from, and in this case, you’ll have to use a LiveCD.

Now you need to overwrite the metadata of the old RAID 1 system; to do it, create a RAID 5 system with the same drives that were included in the RAID 1 system - sdb and sdc - by typing this command:

mdadm --create /dev/md0 -a yes -l 5 -n 2 /dev/sdb1 /dev/sdc1

where l5 sets the array level,

n2 sets the number of drives it includes, and then these drives are specified.

Reload metadata from RAID 1 to RAID 5

When the command is performed, the program will warn you that these drives are already used in a RAID 1 system, so hit Enter to continue.

To check if the conversion was successful, type this command:

cat /proc/mdstat

The rebuilding process

Now all you have to do is to wait until RAID 5 is built: the status of this process is shown here, in percent.

When it is over, the command cat /proc/mdstat will display the following data.

The array is rebuilt into a new type

After that, you can add a new drive to the array, and make it a full-featured RAID 5 system. This new drive will be added as a spare one. Use the following command for this step:

mdadm --add /dev/md0 /dev/sdd1

Adding the third drive

After that, extend the RAID system to the three active drives (now including the spare drive) with this command:

mdadm --grow /dev/md0 --raid-disks=3

Check the result with the command cat /proc/mdstat:

cat /proc/mdstat

Expanding the RAID to a three-disk system

Now you can see that the RAID system is using three drives - sdb, sdc, sdd and the process of conversion (reshape) has begun.

Its progress is shown in percent; wait until it is complete.

In the end, check the disk array for errors with the following command:

e2fsck -f /dev/md0

and use another command to extend it:

resize2fs -p /dev/md0

Checking for errors

Finally, the last command updates the configuration file:

mdadm --examine --scan >> /etc/mdadm.conf

Updating the configuration file

If there are no errors in the course of performing these commands, all the data existing on your RAID 1 system will be transferred onto the new RAID 5.

Mount it and check what’s going on: as you can see, all the files are still here, and the array type has changed to RAID 5.

All files have remained intact

How to convert RAID 0 (striping) into RAID 5 (parity)

However, you can’t use this method to change from RAID 0 to RAID 5 without formatting and losing all the data. Instead, there is a way to convert it quickly with a single command.

Migration from RAID 0 to RAID 5 is only possible when there are two drives - then RAID 0 coincides with RAID 5 in terms of structure. All the changes will affect the array level only, while the information on the drives remains intact.

Here is the command that transforms a RAID 0 consisting of two drives into a RAID 5 including three drives.

mdadm --grow /dev/md0 --level=5 --raid-devices=3 --add /dev/sdd --backup-file=/tmp/grow_md0.bak

Before you run it, unmount the array.

Check the result with the command:

cat /proc/mdstat

Wait until the reshape operation is complete.

Converting RAID 0 into RAID 5

After changing the array type to RAID 5, you can add more drives with the command I have already mentioned in this tutorial:

mdadm --add /dev/md0 /dev/sdc1

Adding drives to the RAID system

After restarting, the array name will change to RAID 5.

If the RAID 0 system contains more than two drives, you need to reduce their number, and only then you’ll be able to convert the array to RAID 5.

How to convert LVRAID1 into LVRAID5

If you used LVM features to create a RAID system, then you can convert it from one array type to another with the command lvconvert:


Run the command


to view the information on this group of disks.

View the information on the drives making up the RAID

If you want to know more about creating MD and LV RAID systems, check one of the previous videos by following the link below.

Go to view
💽 How to Setup Software RAID with MDADM Comand on Linux Ubuntu in 2021 💾

💽 How to Setup Software RAID with MDADM Comand on Linux Ubuntu in 2021 💾

To start the conversion, unmount the logical volume. Type the command:

umount /dev/vg1/lv1

Use the following command to change the RAID level:

lvconvert --type raid5 /dev/vg1/lv1

Convert level one LVM to level five

The last step is to add the third drive to the existing group of disks with this command:

vgextend vg1 /dev/sdd1

When you perform it, the program warns you that the disk is already formatted. Type “y” to confirm your decision and press Enter.

To make sure that the disk is added to the group, use this command:


Now you can see the group consists of three disks.

Add a new drive to the group

Mount the array again and open it in the file manager: all the data is here, nothing is lost.

All the information is preserved

How to convert LVRAID0 into LVRAID5

The same command is used to change from RAID 0 to RAID 5. The only important step is to add the third disk to the group before you start the conversion; otherwise, you’ll see the warning that you don’t have enough space for this command to run.

Add the third disk:

vgextend vg1 /dev/sdd1

Use the following command to change the RAID level:

lvconvert --type raid5 /dev/vg1/lv1

Convert level one LVM to level five

Mount the array and check what information is available. As you can see, all files are here.

All the information has remained unchanged

How to recover data from damaged RAID systems

If there was an error in the process of converting one RAID level into another, or if you erased some information accidentally, use a reliable data recovery tool, – Hetman RAID Recovery. The utility reads from the storage system all the information about the controller, the motherboard, or the software used to create a disk array.

Recover data from damaged RAID arrays inaccessible from a computer.
The program has identified the array without any difficulties

Our product can rebuild the crashed RAID and it lets you copy all critical information from there.

The program has found all deleted data and it can be recovered now

Find more information about recovering MD and LV RAID in one of the previous videos - I’ll put the link in the description as always.

Go to view
🐧 How to Recover Data from Linux-Based Software RAID 0, RAID 1, RAID 5 🐧

🐧 How to Recover Data from Linux-Based Software RAID 0, RAID 1, RAID 5 🐧


Changing from one RAID level to another may take several steps. At first, you convert the array into a interim type, and then transform it into the type you need. For example, to convert RAID 1 into RAID 6, you need to turn it into RAID 5 first, and only then it can be transformed into RAID 6 system.

Vladimir Artiukh

Author: , Technical Writer

Vladimir Artiukh is a technical writer for Hetman Software, as well as the voice and face of their English-speaking YouTube channel, Hetman Software: Data Recovery for Windows. He handles tutorials, how-tos, and detailed reviews on how the company’s tools work with all kinds of data storage devices.

Oleg Afonin

Editor: , Technical Writer

Oleg Afonin is an expert in mobile forensics, data recovery and computer systems. He often attends large data security conferences, and writes several blogs for such resources as, Elcomsoft and Habr. In addition to his online activities, Oleg’s articles are also published in professional magazines. Also, Oleg Afonin is the co-author of a well-known book, Mobile Forensics - Advanced Investigative Strategies.

Recommended For You

Hello! This is AI-based Hetman Software virtual assistant, and it will answer any of your questions right away.
Start Chat