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> I use software RAID1 on Linux using mdadm using whole disk devices (no partitions). > It is important to know that a disk configured to be part of an mdadm R
by kbumsik 8y ago
> I use software RAID1 on Linux using mdadm using whole disk devices (no partitions).
> It is important to know that a disk configured to be part of an mdadm RAID array can look like a broken EFI disk.
I hate to say this, but it is obvious that a software RAID like mdadm cannot grab raw disks as a whole. If the disk doesn't have a valid GPT and EFI partition at the beginning how it is possible to boot from GRUB, load initramfs, and then load mdadm?
I think something must be misconfigured at the first place.
- nh2 8y agoIt's a fully supported use case of mdadm RAID to use bare devices. These are data disks containing no operating system, so there's no booting from them and GRUB doesn't come into play.
- kbumsik 8y agoOh I read the context wrong. I thought he/she used the disks as a bootable disk as well. But do the disks have to have a proper GPT to be safe?
- adamzochowski 8y agoNo. Just like all hardware based raids you can set mdadm to use full raw disk. The GPT is only useful when you want to use part of the disk for RAID - partitioning disk into multiple parts where only some of it will be raided. Some people prefer opposite. First raid raw disks and then partition that md storage. The other reason to put GPT (or old style partition table) is so that no system or tool will mistakenly be helpful with detrcting "uninitiated drive" and then asking to perform quick format.
- blattimwind 8y agoThese disks almost certainly don't contain an operating system, so they don't need to be bootable.
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