[Bug 1608495] Re: IMSM fakeraid handled by mdadm: unclean mounted volumes on shutdown/reboot

[Dimitri John Ledkov]

TO correctly shutdown IMSM/VROC intel matrix raid devices, I expect you
to need to install finalrd & add mdadm finalrd hook.

$ sudo apt install finalrd

Download the attached hook, place it into
/usr/share/finalrd/mdadm.finalrd, mark it executable (sudo chmod +x
/usr/share/finalrd/mdadm.finalrd)

Then reboot twice.

After the second reboot, i expect the raid to come up clean. Please
report back if that helps, and then I should schedule to SRU this change
to bionic.

This is how clean shutdown for IMSM/VROC is implemented in later
releases.

** Attachment added: "mdadm.finalrd"
   https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/1608495/+attachment/5326321/+files/mdadm.finalrd

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to mdadm in Ubuntu.
https://bugs.launchpad.net/bugs/1608495

Title:
  IMSM fakeraid handled by mdadm: unclean mounted volumes on
  shutdown/reboot

Status in mdadm package in Ubuntu:
  Fix Committed
Status in mdadm source package in Xenial:
  Fix Committed
Status in mdadm source package in Yakkety:
  Won't Fix
Status in mdadm source package in Zesty:
  Won't Fix

Bug description:
  Opening this report for Xenial and later as this problem does surface
  again due to moving to systemd.

  Background:

  mdadm is used to create md raid volumes based on Intel Matrix Storage
  Manager fakeraid metadata. The setup usually consists of a container
  set that contains one or more raid volumes. Which is the reason that
  those fakeraid volume are more affected by timing issues on
  shutdown/reboot.

  In my specific setup I am using one of the IMSM raid volumes as a LVM
  PV and one LV of that is mounted as /home. The problem is that
  unmounting /home on shutdown/reboot will update the filesystem
  superblock which causes the raid state to become dirty for a small
  period of time. For that reason with sysvinit scripts there is a
  mdadm-waitidle script which *must* be run after the umountroot (or for
  /home at least after umountfs) script has run.

  With Xenial both umountroot and umountfs are softlinks to /dev/null in /lib/systemd/system, so I am not sure they are good to cause the mdadm-waitidle to be delayed *after* all filesystems are unmounted.
  Practically I see that if /home is mounted on shutdown/reboot, the raid set will go into a full resync the next time I boot (additional pain but different problem: the resync appears to be much more aggressive than in the past, delaying boot a lot and rendering the system barely usable until it finishes). If I manually unmount /home before the reboot, the raid set is good.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/1608495/+subscriptions