[Bug 1722491] Re: rootfs on Intel Matrix Raid hangs or shuts down not clean

[Launchpad Bug Tracker]

This bug was fixed in the package mdadm - 3.3-2ubuntu7.5

---------------
mdadm (3.3-2ubuntu7.5) xenial; urgency=medium

  * Add systemd shutdown script which waits for arrays to be clean during
    shutdown phase.
  * Do not take over initramfs mdmon services, and continue running them
    off initrd to avoid killing mdmon processes before systemd attempts dm
    detach and hang. As systemd in xenial does not appear to honor
    sendsigs.omit.d.
  * Add mdadm-shutdown.service which is recommended to be used on systems
    with Intel Matrix / DDF raid. It creates a shutdown initramfs which
    systemd-shutdown may pivot to, and complete clean external metadata
    raid array shutdown.
  * LP: #1722491

 -- Dimitri John Ledkov <xnox at ubuntu.com>  Mon, 09 Oct 2017 14:56:09
+0100

** Changed in: mdadm (Ubuntu Xenial)
       Status: Fix Committed => Fix Released

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https://bugs.launchpad.net/bugs/1722491

Title:
  rootfs on Intel Matrix Raid hangs or shuts down not clean

Status in mdadm package in Ubuntu:
  Fix Released
Status in mdadm source package in Xenial:
  Fix Released
Status in mdadm source package in Zesty:
  Fix Released

Bug description:
  [Impact]

   * In xenial, mdadm-waitclean is an init.d script, and it appears that
  it doesn't not run late enough. In later releases a systemd-shutdown
  script is shipped instead. Which results in wait-clean action executed
  later in the shutdown cycle, having more chances to complete the
  shutdown with clean/synced RAID array state.

   * In xenial, there is no default shutdown initramfs, and therefore
  mdmon processes are killed before the Intel Matrix RAID / DFF external
  metadata RAID arrays are stopped. This leads to a full resync upon
  next assembly. One options is to implement a shutdown initramfs. This
  is now integrated in he package a mdadm-shutdown.service, optional
  command.

   * In xenial, systemd does not support sendsigs.omit.d, and therefore
  this results in mdmon process being killed prematurely. Thus keep
  mdmon processes started in the initramfs running - such that systemd-
  shutdown can unmount dm held nodes. Ideally systemd on xenial should
  honor sendsigs.omit.d pid-files, or mdmon processes should be migrated
  to be udev rules activated - but such a change, imho, is too risky for
  an sru.

  [Bugfix]
  * Backport mdadm.shutdown systemd-shutdown script to xenial
  * Backport mdadm-shutdown.service job

  [Test Case]

   * Switch logging to console, and make it verbose LogLevel=debug LogTarget=console. Perform shutdown and observe that mdadm.shutdown is executed during shutdown.
   * Check that the system boots with a clean raid-array state.

   * Install system with root on Intel Matrix or DDF raid
   * Install dracut-core and activate mdadm-shutdown.service
   * Reboot
   * System should reboot cleanly, with Intel Matrix raid array synced

  [Regression Potential]

   * On systems that have rootfs on the Intel Matrix / DDF raid
  (external metadata mdadm raid, i.e. NOT the generic linux raid)
  initramfs will result in being held up through the lifetime of the
  boot thus using more steady state RAM. This only affects systems that
  use Intel Matrix / DDF controllers, and are typically bare-metal
  servers.

   * additional wait-clean shutdown script is quick but has an impact on
  shutdown.target speed / time to shutdown or reboot.

   *

  [Other Info]

   * Later releases do not use sysv-init script thus this not a direct
  backport of code from later releases

  Roughly corresponds to https://tracker.debian.org/news/878208 & parts
  of
  https://browse.dgit.debian.org/mdadm.git/commit/?id=61c54b388ce54b8129d039aa6d422aaca0dd0e77
  specifically shipment of the mdadm.shutdown script

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