On 11/10/20 7:47 AM, Matti Pulkkinen wrote:
> Samuel Sieb kirjoitti 7.11.2020 klo 0.11:
>> The current recommendation is to not use any RAID options with btrfs
>> right now. Use mdraid underneath instead.
>
> Could you elaborate on why this is? Is there a way to select which type
> of RAID to use in Anaconda?
There was an explanation a while back on the -devel list during the
discussion about making btrfs the default. I think that RAID5 and 6 are
not working well for some reason. RAID1 is ok, but just be aware that
by default, you can't boot from a degraded RAID without fixing it first.
You should get dropped to a shell where you can
mount -o degraded,subvol=root /sysroot
exit
And then use 'btrfs replace' to replace old for new drive. Currently it requires new to be same size or bigger than old. Once it completes use 'btrfs filesystem resize'.
Write up on using Btrfs parity raid:
Most problems can be avoided by using raid1 for metadata (the filesystem itself), i.e.
mkfs.btrfs -mraid1 -draid5
Or
mkfs.btrfs -mraid1c3 -draid6
But yeah, raid is not a backup
---
Chris Murphy