Grub issue after updating to Cobia and upgrading zpools (-a) (Solved)

[pixelwave]

I updated to TrueNAS Scale Cobia and unfortunately upgraded all zpools (including the boot pool) via "zpool upgrade -a"

Now when booting I get the error (truenas running as VM on proxmox):

Error: unknown filesystem.
grub rescue>

Now after some research I learned that it is not good to upgrade also the boot pool and in general it is more safe to do via the web GUI.

Any chances of getting system back running without reinstall?

 

[Arwen]

No.

But, if you have your configuration saved, you re-install the boot-device, boot to it, restore your configuration and you are done. In theory, 30 minutes of time.

 

[pixelwave]

Yepp - just did that. Works again.

 

[Arwen]

Great.

Back to the cause.

You never want to upgrade the pool features for the boot-pool.

In general, you don't want to upgrade your data pool features right away. And in theory, you want to only add features that are also available on a prior TrueNAS update. Basically, you can add pool features item by item. For example, whence ZSTD compression becomes common, and exists in prior updates, you may want to enable it as a pool feature and use it on some datasets.

 

[Sawtaytoes]

Cross-linking to these other forum posts, since I assume a bunch of people are gonna have this same issue and will have slight variations solutions they need:
- https://www.truenas.com/community/threads/23-10-0-grub-boot-screen-after-zfs-upgrade.113852
- https://forum.level1techs.com/t/tot...0-by-upgrading-bootpool-with-no-backup/203656
- https://www.truenas.com/community/threads/truenas-scale-23-10-rc-1-grub-issue.112994/