Advisories ยป MGAA-2015-0166

Updated mdadm packages fixes IMSM metadata handling

Publication date: 02 Nov 2015
Modification date: 02 Nov 2015
Type: bugfix
Affected Mageia releases : 5

Description

This mdadm maintenance update fixes handling of disks with IMSM metadata,
and various other minor issues.

In mdadm-3.3 a change was made to how IMSM (Intel Matrix Storage Manager)
metadata was handled. Previously an IMSM array would only be assembled
if it was attached to an IMSM controller.

In 3.3 this was relaxed as there are circumstances where the controller is
not properly detected. Unfortunately this has negative consequences which
have only just come to light.

If you have an IMSM RAID1 configured and then disable RAID in the BIOS,
the metadata will remain on the devices. If you then install some other OS
on one device and then install Linux on the other, Linux might eventually
start noticing the IMSM metadata (depending a bit on whether mdadm is
included in the initramfs) and might start up the RAID1. This could copy
one device over the other, thus trashing one of the installations.

Note, in Mageia 5 we are using dmraid instead of mdadm for IMSM by
default, thereby mitigating this issue.

References

SRPMS

5/core