[Bug 1722491] Re: improve mdadm imsm integration with systemd

[Dimitri John Ledkov]

** Description changed:

  [Impact]
  
-  * In xenial, mdadm-waitclean is an init.d script, and it appears that
+  * 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
+  * 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, another
  solution is to not takeover mdmon process from the initramfs. This will
  result in holding up initramfs memory throughout the lifetime of the
  system, however the net effect should be clean raid array shutdowns
  which will mitigate excessive resyncs.
  
- 
  [Bugfix]
  Backport mdadm.shutdown systemd-shutdown script to xenial
  
  [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.
+  * 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.
  
  [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.
+  * 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
+ 
+  * 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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https://bugs.launchpad.net/bugs/1722491

Title:
  improve mdadm imsm integration with systemd

Status in mdadm package in Ubuntu:
  New
Status in mdadm source package in Xenial:
  New

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,
  another solution is to not takeover mdmon process from the initramfs.
  This will result in holding up initramfs memory throughout the
  lifetime of the system, however the net effect should be clean raid
  array shutdowns which will mitigate excessive resyncs.

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

  [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.

  [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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