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HoseinLavaei

Member

Registered: 2023-11-04

Posts: 8

Raid 0 setup forgot to change partition type to Linux raid

I have 4 disks:
/dev/sda
/dev/sdb
/dev/sdc
/dev/sdd

I wanted to make 2 raid 0 disks :
/dev/md/hdd from /dev/sda and /dev/sdc
/dev/md/ssd from /dev/sdb and /dev/sdd

I made these and partitioned them to install arch on of them but I forget to set partition type to Linux RAID and I set their type to Linux filesystem and Linux home.

After reboot my UEFI bios wasn't able to load bootloader so I booted into archiso and found out that. mdadm can't recognize raid system and fdisk shows that my disks don't have any partition at all and recognize them as free space.

When I want to assemble those disks via mdadm it gives error and tells me that I don't have any raid device

My question is all my files gone? If not can I recover them? And how?

frostschutz

Member

Registered: 2013-11-15

Posts: 1,532

Re: Raid 0 setup forgot to change partition type to Linux raid

If it is as described (md raid from sda, sdc, instead of sda1, sdc1, or similar) then you were using raid without partition table. If you created a partition table on these drives afterwards, you killed your md metadata with it. (This is why you should always use partitions, not bare drives, for anything).

If you create your raid again exactly the same way as before (same drives, drive order, raid level, chunk size, layout, offset, metadata version ...) then your data might reappear... this is a problem for older arrays since mdadm defaults change over time, but if you created it recently it might "just work". It would help if you knew exactly which drive was which - drive letters sd[abcd] can change randomly.

The Linux RAID partition type is optional (only mandatory for outdated, raid auto assembly, which only works with 0.90 metadata anyway). Not really necessary to set this type at all.

Last edited by frostschutz (2024-07-29 20:24:25)

HoseinLavaei

Member

Registered: 2023-11-04

Posts: 8

Re: Raid 0 setup forgot to change partition type to Linux raid

Yes I seted-up on raw disk not partition table.but wiki says that it can be done but recommend:
https://wiki.archlinux.org/title/RAID#P … he_devices. The note
Does it mean the wiki is outdated?
Thanks anyway

frostschutz

Member

Registered: 2013-11-15

Posts: 1,532

Re: Raid 0 setup forgot to change partition type to Linux raid

It should not be done. There is also nothing to gain from it. Best case you get 1 MiB more storage space. Worst case your data is gone. Not worth the risk.

RAID-0 is also a risky choice (there is zero redundancy). But you probably already know.

Last edited by frostschutz (2024-07-30 06:36:55)

HoseinLavaei

Member

Registered: 2023-11-04

Posts: 8

Re: Raid 0 setup forgot to change partition type to Linux raid

Thanks