Why shouldn't I use striping raid on the partition I boot from?

Question

You should not use any form of striping such as RAID-0 or RAID-5 on the partition you boot from.

Why is this? I've never seen a similar warning before. Grub supports booting from a raid0 disk, and the kernel supports it as long as the modules are compiled in. Is there anything else I'm missing?

Edit: Arch Linux's section on raid mentions nothing in regards to striped raid in particular. Is this warning specific to Gentoo?

score 3 · Accepted Answer · edited Apr 13 '17 at 12:37

3

Because your boot loader (e.g. grub) won't know how to read from RAID-0 or RAID-5. Where did you find information that grub supports raid0?

You should have a small RAID-1 /boot partition.

UPDATE: I was wrong.

Turns out grub does support raid1 and raid5. However, there's some confusion about what metadata formats it supports, so I guess warning in the Gentoo guide is there for safety.

However, all the guides I've seen before say to use raid1, so raid1/raid5 does not seem like well tested configuration, so I'd still recommend to avoid it.

edited Apr 13 '17 at 12:37

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answered Apr 22 '16 at 16:51

rvs

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I don't know where I read that, seems your right; Thanks! – Shelvacu Apr 22 '16 at 17:19
Aha! Here: https://wiki.archlinux.org/index.php/GRUB#RAID "You may use mdadm for RAID 5/6, which is supported by GRUB." – Shelvacu Apr 22 '16 at 17:50
@shelvacu huh, looks like I was wrong. I've edited my answer. TIL. – rvs Apr 22 '16 at 20:40

Why shouldn't I use striping raid on the partition I boot from?

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