[Bug 1678112] Re: lvm cache support lost in zesty

[Dimitri John Ledkov]

grub2 used to support lvm2 cache partitions, in a buggy way, corrupting
them on boot/grubenv read or write.

this was disabled.

the next upstream grub2 release has proper support for lvm2 cache
partition, thus this may come back whenever 2.06 lands.

it will not be backported.

Please use separate /boot partition for grub without lvm2 caching, if
you want to use lvm2 caching for your regular rootfs.

** Changed in: grub2 (Ubuntu)
       Status: Confirmed => Won't Fix

-- 
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/1678112

Title:
  lvm cache support lost in zesty

Status in grub2 package in Ubuntu:
  Won't Fix

Bug description:
  grub fails to work when araid1 lvm volume exists that is cached in zesty.
  grub version 2.02~beta3-4ubuntu1
  The same configuration worked on yakkety

  ~$ sudo update-grub2
  Generating grub configuration file ...
  Found linux image: /boot/vmlinuz-4.10.0-14-generic
  Found initrd image: /boot/initrd.img-4.10.0-14-generic
  Found linux image: /boot/vmlinuz-4.8.0-45-generic
  Found initrd image: /boot/initrd.img-4.8.0-45-generic
  Found memtest86+ image: /memtest86+.elf
  Found memtest86+ image: /memtest86+.bin
  Found Windows 7 on /dev/sdc4
  Found Debian GNU/Linux wheezy/sid on /dev/mapper/lvm-debian
  Found Ubuntu 15.04 (15.04) on /dev/mapper/lvm-root2
  Found Ubuntu 14.04.1 LTS (14.04) on /dev/mapper/lvm-root3

  $ sudo lvcreate --type raid1 -L 1G lvm -n testing
    Logical volume "testing" created.
  ~$ sudo lvcreate --type cache --cachemode writeback -L 10G -n ssdcachetest lvm/testing /dev/sda1
    Using default stripesize 64.00 KiB.
    WARNING: Data redundancy is lost with writeback caching of raid logical volume!
    Logical volume lvm/testing is now cached.

  ~$ sudo update-grub2
  Generating grub configuration file ...
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  error: invalid segment.
  grub-probe: error: disk `lvmid/OwVp3J-KH9N-RcXl-Fh3J-ZEiZ-egg4-JRffI3/7Dieap-dj1i-dHiz-eLfa-c7be-IiyB-GaHL26' not found.

  removing the cache fixes the issue.

  lvmid/OwVp3J-KH9N-RcXl-Fh3J-ZEiZ-egg4-JRffI3/7Dieap-dj1i-dHiz-eLfa-c7be-IiyB-GaHL26 is my boot lvm partition which is a regular uncached linear partition.
    --- Logical volume ---
    LV Path                /dev/lvm/boot
    LV Name                boot
    VG Name                lvm
    LV UUID                7Dieap-dj1i-dHiz-eLfa-c7be-IiyB-GaHL26
    LV Write Access        read/write
    LV Creation host, time ubuntu, 2015-09-27 23:22:37 +0200
    LV Status              available
    # open                 1
    LV Size                1.00 GiB
    Current LE             256
    Segments               1
    Allocation             inherit
    Read ahead sectors     auto
    - currently set to     256
    Block device           253:2

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1678112/+subscriptions