PVE 8.3 node with btrfs booting into grub command line after hard reset

[Fantu]

Also on btrfs you can remove the disk and mount with degraded option.
Instead do remove, convert profile with balance, readd later and reconvert profile the best is doing only replace.
Anyway replace is good with only disk issue, but if not sure is the disk issue can be other things (like adapter) that remain risk to have issue also with new disk on replace.

If you convert to single profile keeping one disk I suggest to use dup profile for metadata so you can have more resistance and possible self-repair at least for the most delicate part without consuming much space.
For example, I always use duplicate at least for metadata, dup profile on fs with one disk or raid1 with 2 or more disks.
For details on btrfs profiles: https://wiki.tnonline.net/w/Btrfs/Profiles#Profiles_Overview

EDIT:
for the replace cases there is also this article that is good: https://wiki.tnonline.net/w/Btrfs/Replacing_a_disk

 

[udotirol]

thanks a lot, this is really much appreciated!

 

[marclava]

Hi, this is my first post.

I installed Proxmox with the experimental btrfs RAID1 boot option; one of the disk had errors, and when I tried to reboot the system it started a grub shell. Then I removed the faulty disk and Proxmox was able to boot in degraded mode. So it's still working, but it's not ideal...

What would be the procedure to either:
- replace the faulty disk and rebuild the RAID1
- remove the RAID1 config so that the working disk does not boot in degraded mode.
- transfer everything to a new disk, not using RAID1 anymore, and from now on use a backup to restore the whole system in case of a disk crash.

Thanks!

Edit:
I had to reinstall everything, this time using a single SSD (not a RAID1). So I tried with the 8.3 installer but it was unable to install grub, and I even tried with two different drives, using wipefs to make sure the drives were properly initialized... So I tried again with the 8.2 installer, and it worked! Then I updated to 8.3 (using apt) and it's still working. My impression is that something is broken in the 8.3 installer, and also that the BTRFS RAID1 root install feature is not ready for production use (or that I'm not experienced enough with BTRFS). I learned that it's easier to use a single drive with the default option (ext4 LVM) and restore from backups (in case of a major problem).