[Bug 1867007] Re: ZFS won't boot if multiple rpools found

[Jean-Baptiste Lallement]

** Package changed: grub2 (Ubuntu) => zfs-linux (Ubuntu)

** Changed in: zfs-linux (Ubuntu)
   Importance: Undecided => Medium

** Changed in: zfs-linux (Ubuntu)
       Status: New => Triaged

** Summary changed:

- ZFS won't boot if multiple rpools found
+ zfs-initramfs fails with multiple rpool on separate disks

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to grub2 in Ubuntu.
https://bugs.launchpad.net/bugs/1867007

Title:
  zfs-initramfs fails with multiple rpool on separate disks

Status in zfs-linux package in Ubuntu:
  Triaged

Bug description:
  I had an Ubuntu old installation that used a ZFS root, using the
  layout described in the ZFS on Linux docs. Consequently, the pool name
  for my Ubuntu installation was "rpool". I'm currently encountering an
  issue with that pool that only allows me to mount it read-only. So,
  I'd like to replicate the datasets from there to a new device.

  On the new device, I've set up a ZFS system using the Ubuntu 20.04
  daily installer (March 9, 2020). This setup creates a new pool named
  "rpool". So, with both devices inserted, I have two distinct pools
  each named "rpool", one of which will kernel panic if I try to mount
  it read-write.

  ZFS is fine with having multiple pools with the same name. In these
  cases, you use `zfs import` with the pool's GUID and give it a
  distinct pool name on import. However, the grub config for booting
  from ZFS doesn't appear to handle multiple pools with the same rpool
  name very well. Rather than using the pool's GUID, it uses the name,
  and as such, it's unable to boot properly when another pool with the
  name "rpool" is attached to the system.

  I think it'd be better if the config were written in such a way that
  `update-grub` generated boot config bound to whatever pool it found at
  the time of its invocation, and not start searching through all pools
  dynamically upon boot. Just to be clear, I have an Ubuntu 20.04 system
  with a ZFS root that boots just fine. But, the moment I attach the old
  pool, also named "rpool", I'm no longer able to boot up my system even
  though I haven't removed the good pool and I haven't re-run `update-
  grub`. Instead of botoing, I'm thrown into the grub command line.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/zfs-linux/+bug/1867007/+subscriptions