Add raid to existing Ubuntu desktop install

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.

2 Answers

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

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: