[->UUIDudev] installing mdadm (or outdated mdadm.conf) breaks bootup
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
mdadm (Ubuntu) |
Triaged
|
High
|
Unassigned | ||
Bug Description
Original Report (also confirmed with 9.10 and 10.04 beta1):
On a freshly installed ubuntu-
When the 'mdadm' package is installed, the system fails to boot successfully, and ends up at the initrd '(busybox)' prompt.
Hardware: DELL 1950 - 1RU Server
HDD: SAS
To get the server booting again you need to revert to the old initramfs:
- Boot with ubuntu-
- ALT-F2 to start other shell
- 'fdisk -l' to see details of available drives.
- mkdir /mnt/disk
- mount -t ext3 /dev/sdb1 /mnt/disk
- cd /mnt/disk/boot
- mv initrd-
- cp initrd-
- sync
- reboot
---
Diagnose:
-> This is mdadm setting up arrays according to unreliable superblock information (device "minor" numbers, labels, hostnames) combined with the idea of fixing the unreliability by limiting array assembly with information from mdadm.conf (PARTITIONS, ARRAY, HOMEHOST lines) which just reassigns the unsolvable conflict handling problem to setup tools, admins and installers. It forces them to create mdadm.conf files. And of course they fail.
In cases where old superblocks are found on the disks during mdadm install, they are added to ARRAY definitions (that really shouldn't need to be there at all) in mdadm.conf, and copied over into the initramfs. During next boot the system can not assemble these (incomplete) arrays.
Cure:
Systematically prevent conflicts from arising instead of relying on mdadm.conf maintanance. -> Do not depend on mdadm.conf definitions but use UUID-based array assembly as described in comment #33
description: | updated |
summary: |
- Installing mdadm or outdated mdadm.conf breaks bootup + Installing mdadm (or outdated mdadm.conf) breaks bootup |
summary: |
- Installing mdadm (or outdated mdadm.conf) breaks bootup + [->UUIDudev] installing mdadm (or outdated mdadm.conf) breaks bootup |
description: | updated |
description: | updated |
description: | updated |
description: | updated |
description: | updated |
Version: mdadm 2.6.2-1ubuntu2