[SOLVED] rescue mode with root on zfs trouble

diversity

Active Member
Feb 19, 2020
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TL;DR update.
I used the ubuntu 22.04.1 ISO and things worked out great.
end TL;DR update.

I am running a fresh install of
pve-manager/7.1-11/8d529482 (running kernel: 5.13.19-6-pve)
on bare metal
using a zfs mirrored root
Code:
 pool: rpool

 state: ONLINE

  scan: scrub repaired 0B in 00:00:02 with 0 errors on Sun Mar 13 00:24:03 2022

config:


        NAME                                 STATE     READ WRITE CKSUM

        rpool                                ONLINE       0     0     0

          mirror-0                           ONLINE       0     0     0

            nvme-eui.6479a72960213634-part3  ONLINE       0     0     0

            nvme-eui.6479a73050830000-part3  ONLINE       0     0     0


errors: No known data errors

I made a few snapshots
Code:
NAME                             USED  AVAIL     REFER  MOUNTPOINT
rpool/ROOT/pve-1@fresh_install   228M      -     1.61G  -
rpool/ROOT/pve-1@updated         104M      -     1.94G  -

then made some changes to system to see if I can rollback and remove all changes.

So I used the usb drive I used for installing this machine (iso installer 7.1) and selected rescue mode.

Then I was greeted by these errors

Code:
Error: Compression algorithm inherit not supported
.
Error: Compression algorithm inherit not supported
.
Error: Compression algorithm inherit not supported
.
Error: Compression algorithm inherit not supported
.
ERROR: unable to find boot disk automatically

Press any key to continue

When pressing any key I get back to where I came from so basically ending up in a loop.

What is the correct procedure to use rescue mode on the latest updated PVE? So that I can rollback to a snapshot of /rpool/ROOT/pve-1
 
Last edited:
It could be that 7.1-11 has newer ZFS support (zfsutils-linux: 2.1.2-pve1) than your 7.1 ISO. Did you use 7.1-1 or 7.1-2? And your rpool has already been upgraded to enable all new features. If that's the case, I'm afraid you need to wait for the next Proxmox ISO or find another Linux Live CD that has the latest ZFS support to boot the system and rollback to the snapshot.
 
uggg, bad idea. too buggy and also no access (for newcommers like me) to the actual system root. I seme to only have access to the in memory system.

does one have any suggestions on what live usb with up to date zfs support I can use to salvage recent PVE zfs installs?
 
hahah I am sure I am not making any sense but I've gotten half a mind to install the most basic of linux on bare metal and then run PVE as a VM.

Sure this is just me being a bit frantic for now so I'd really still like to learn how to deal with my current situation.

But it is just a thought that I throw out into the wild
 
It could be that 7.1-11 has newer ZFS support (zfsutils-linux: 2.1.2-pve1) than your 7.1 ISO. Did you use 7.1-1 or 7.1-2? And your rpool has already been upgraded to enable all new features. If that's the case, I'm afraid you need to wait for the next Proxmox ISO or find another Linux Live CD that has the latest ZFS support to boot the system and rollback to the snapshot.
Hi,
is there a fix about this? with the latest ISO/USB I get a similar "Error: Compression algorithm 79..." and Im trying to find a way to fix boot...
thanks
 
I am sad to learn it is still broken :(

I decided to wait until pve 7.2 rescue/installer was out in the hopes things will be fixed by then but I see now it is already released so once I am back from holiday I will try that once.
Or is that the one you used? as you did say 'latest ISO/USB'

If someone finds a fix please share it here.
 
Last edited:
FYI: this is still broken. On v7.3-1 the rescue boot will only print "Compression algorithm 84 is not supported" when trying to run the rescue boot.
 
it could be a soft nudge towards the backup services.

I think I do not know what I am talking about
 
it could be a soft nudge towards the backup services.

I think I do not know what I am talking about
Backup service wouldn't help you if you want to recover a production system quickly. Backup is more a DR solution. I think it's simply because Linux module uses compression algo which isn't supported by GRUB module, and even if booted in UEFI mode it still relies on GRUB to provide rootfs mounting.
 

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