Creating an Exact Copy of Two Drives on a Single RAID1 Device with Ubuntu
In this article, we will discuss the process of creating an exact copy of two drives on a single RAID1 device using Ubuntu. This method utilizes the dd command to clone the drives, followed by setting up a RAID1 array with the two cloned drives for redundancy and fault tolerance.
Prerequisites
Before we begin, make sure you have the following:
- Two identical hard drives or SSDs (preferably at least 500 GB each)
- A system with Ubuntu installed, and enough space to temporarily store the cloned drives (at least the size of one drive)
Cloning the Drives with dd
First, connect and power on the two drives. Open a terminal and determine the device names for your source (source_drive) and destination (destination_drive) drives, for example, /dev/sda and /dev/sdb:
sudo fdisk -l
Next, unmount any active partitions on the destination drive:
sudo umount /dev/sdX*
Replace sdX with the appropriate letter for the destination drive. Now, we can proceed to clone the source drive to the destination drive:
sudo dd if=/dev/source_drive of=/dev/destination_drive bs=64K status=progress oflag=sync
This may take a while, depending on the size of the drive.
Creating a RAID1 Array
Once the cloning process is complete, you can create a RAID1 array:
sudo mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdX1 /dev/sdY1
Replace sdX1 and sdY1 with the appropriate partition names for the first partitions of the cloned drives. After running the command above, the RAID1 array (/dev/md0) will be created using the two partitions.
Formatting and Mounting the RAID Array
Now, format the RAID array:
sudo mkfs.ext4 /dev/md0
After formatting, you can mount the RAID array. For instance, create a new directory for the mount point and then:
sudo mount /dev/md0 /mnt/raid_array
Copying Data to the RAID Array
Since the destination drive is an exact copy of the source drive, all data already exists on the RAID array. However, you can ensure data integrity by running a checksum verification:
sudo md5sum /dev/source_drive > /mnt/raid_array/source_drive_checksum.txt
sudo md5sum /dev/destination_drive > /mnt/raid_array/destination_drive_checksum.txt
Compare the checksums and confirm their equivalence.
- Cloned two drives using the
ddcommand - Created a RAID1 array using the two cloned drives
- Mounted the RAID1 array
- Verified data integrity with a checksum verification