Degraded array check, may not do what it says it's doing

Bug #1279741 reported by Dimitri John Ledkov on 2014-02-13
This bug affects 3 people
Affects Status Importance Assigned to Milestone
mdadm (Ubuntu)

Bug Description

Degraded array check in the initramfs currently does:
mdadm --misc --scan --detail --test

and checks the return code. I happen to be using Intel Matrix Raid (container type), thus as it happens the container, and arrays are already assembled -> all arrays active, one disk active, one spare and rebuilding. At this state mdadm --misc --scan --detail --test returns error code 2, but it is to late to do anything but simply use that active array and continue to boot...

So degraded_array question should die.

We should attempt starting arrays with --no-degraded a few times, and after a timeout assemble them with --run, and if we don't have enough drives to start the array only then fall through to initramfs recovery shell.

Launchpad Janitor (janitor) wrote :

This bug was fixed in the package mdadm - 3.2.5-5ubuntu3

mdadm (3.2.5-5ubuntu3) trusty; urgency=medium

  * Drop precise-sru-reverts.patch, which disabled imsm/ddf raid assembly.
  * Take kernel cmdline parameters "nomdmonisw" and "nomdmonddf" into
    account, when assembling imsm/ddf arrays. This defaults to assembling
    those arrays using mdmon/mdadm, with a fallback to dmraid upon
  * Add breaks on dmraid, of versions that assemble fakeraid devices by
  * Drop degraded array questions, since the degraded check results in
    false negatives (e.g. all drives present & started arrays, yet
    resyncing) assemble arrays as best as is possible. (LP: #1279741)
  * Use default/grub.d snippet to continue using dmraid to assemble
    fakeraid arrays.
 -- Dimitri John Ledkov <email address hidden> Tue, 18 Feb 2014 09:12:20 +0000

Changed in mdadm (Ubuntu):
status: New → Fix Released
Ubuntu QA Website (ubuntuqa) wrote :

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:

tags: added: iso-testing
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