Add raid to existing Ubuntu desktop install

Question

I have a desktop with Ubuntu installed on an SSD. Can I add 4 more drives and put them in RAID 5 (turn it into a NAS) without reinstalling? If so how? Thanks.

Answer 1

You can create a raid5 array with the additional disks using the "mdadm" package. Check How To Create Raid Arrays with mdadm

Answer 2

I wanted to create a RAID 0 array for a high performance video transcoding workstation that I built utilizing a pair of M2 PCIE SSD drives. Everything I had found recommended installing Ubuntu server in order to accomplish this. I didn't think that was necessary for my use case.

I had originally setup the system for dual boot WIN10 and Ubuntu using one drive for Windows 10 and the other for Ubuntu 16.04. UEFI was giving me fits so I enabled CSM in the BIOS and attempted Legacy installations of both OS. I shrank both installations (and moved the swap partition) to leave roughly 1/2 the space on each drive (55.9G in my case) unallocated for my planned RAID 0 volume.

I utilized fdisk to create the necessary partitions of type fd on both drives in the remaining space.

Here's the end result on the Windows drive:

Device         Boot     Start       End   Sectors  Size Id Type
/dev/nvme0n1p1 *         2048   1126399   1124352  549M  7 HPFS/NTFS/exFAT
/dev/nvme0n1p2        1126400 117221375 116094976 55.4G  7 HPFS/NTFS/exFAT
/dev/nvme0n1p3      117221376 234441647 117220272 55.9G fd Linux raid autodetect

and the Ubuntu drive:

Device             Start       End   Sectors  Size Type
/dev/nvme1n1p1      2048      4095      2048    1M BIOS boot
/dev/nvme1n1p2      4096 100247551 100243456 47.8G Linux filesystem
/dev/nvme1n1p3 100247552 117221375  16973824  8.1G Linux swap
/dev/nvme1n1p4 117221376 234441614 117220239 55.9G Linux RAID

I installed mdadm with sudo apt install mdadm and then configured.

I checked that both drives were detected and partitioned properly with lsblk

nvme0n1     259:0    0 111.8G  0 disk  
├─nvme0n1p1 259:3    0   549M  0 part  
├─nvme0n1p2 259:10   0  55.4G  0 part  
└─nvme0n1p3 259:11   0  55.9G  0 part  
nvme1n1     259:1    0 111.8G  0 disk  
├─nvme1n1p1 259:4    0     1M  0 part  
├─nvme1n1p2 259:5    0  47.8G  0 part  /
├─nvme1n1p3 259:6    0   8.1G  0 part  
└─nvme1n1p4 259:2    0  55.9G  0 part 

I created the Array with the command `sudo mdadm -C /dev/md0 -l raid0 -n 2 /dev/nvme0n1p3 /dev/nvme1n1p4

I checked the status with

:~$ cat /proc/mdstat
Personalities : [raid0] 
md0 : active raid0 nvme1n1p4[1] nvme0n1p3[0]
      117153792 blocks super 1.2 512k chunks

unused devices: <none>

mdadm --detail /dev/md0 provides more detailed info:

/dev/md0:
        Version : 1.2
  Creation Time : Tue Sep 11 10:31:25 2018
     Raid Level : raid0
     Array Size : 117153792 (111.73 GiB 119.97 GB)
   Raid Devices : 2
  Total Devices : 2
    Persistence : Superblock is persistent

    Update Time : Tue Sep 11 10:31:25 2018
          State : clean 
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

     Chunk Size : 512K

           Name : me-Z370-HD3P:0  (local to host me-Z370-HD3P)
           UUID : bd71c1dd:2eb9fbd6:66204362:dcf71a05
         Events : 0

    Number   Major   Minor   RaidDevice State
       0     259       11        0      active sync   /dev/nvme0n1p3
       1     259        2        1      active sync   /dev/nvme1n1p4

Made the filesystem with mkfs.ext4 /dev/md0 and mounted it with sudo -i

# mkdir /mnt/raid0
# mount /dev/md0 /mnt/raid0/

All that remains is to benchmark it:

` and create an fstab entry to automount it at at startup.

Sources: https://www.tecmint.com/create-raid0-in-linux/