Bug#844640: mdadm: Newly-created array doesn't assemble at boot - related to hostname change?

[Andy Smith]

On Thu, Nov 17, 2016 at 06:23:08PM +0000, Andy Smith wrote:
> After install, the server's hostname was changed to "jfd".
> 
> An additional array (md5) was created using member devices /dev/sd{c,d}.
> It was added to /etc/mdadm/mdadm.conf and update-initramfs -u was
> called.
> 
> This array does not assemble during boot.

I've found a work-around.

I noticed that mpt3sas driver wasn't being loaded in the initramfs,
probably because none of the drives on it are required to boot the
system.

I added mpt3sas to /etc/initramfs-tools/modules and then all drives
are seen during initramfs, and arrays are assembled:

Begin: Loading essential drivers ... done.
Begin: Running /scripts/init-premount ... done.
Begin: Mounting root file system ... Begin: Running /scripts/local-top ... Begin: Assembling all MD arrays ... [   40.1
58317] random: nonblocking pool is initialized
[   40.161795] md: bind<sdf1>
[   40.162161] md: bind<sde1>
[   40.163226] md: raid1 personality registered for level 1
[   40.163654] md/raid1:md0: active with 2 out of 2 mirrors
[   40.163745] md0: detected capacity change from 0 to 510328832
[   40.164259]  md0: unknown partition table
mdadm: /dev/md/0 has been started with 2 drives.
[   40.176662] md: bind<sdf2>
[   40.177235] md: bind<sde2>
[   40.178332] md: raid10 personality registered for level 10
[   40.178656] md/raid10:md1: active with 2 out of 2 devices
[   40.178746] md1: detected capacity change from 0 to 1998585856
[   40.179170]  md1: unknown partition table
mdadm: /dev/md/1 has been started with 2 drives.
[   40.189887] md: md2 stopped.
[   40.191292] md: bind<sdf3>
[   40.191498] md: bind<sde3>
[   40.192705] md/raid10:md2: active with 2 out of 2 devices
[   40.192797] md2: detected capacity change from 0 to 999292928
[   40.193128]  md2: unknown partition table
mdadm: /dev/md/2 has been started with 2 drives.
[   40.204234] md: md3 stopped.
[   40.205278] md: bind<sdf5>
[   40.205695] md: bind<sde5>
[   40.206613] md/raid10:md3: active with 2 out of 2 devices
[   40.206704] md3: detected capacity change from 0 to 12492734464
[   40.207094]  md3: unknown partition table
mdadm: /dev/md/3 has been started with 2 drives.
[   40.218963] md: md5 stopped.
[   40.223807]  sdb: unknown partition table
[   40.228841]  sda: unknown partition table
[   40.229044] md: bind<sda>
[   40.229613] md: bind<sdb>
[   40.234024]  sdb: unknown partition table
[   40.243686] md/raid10:md5: active with 2 out of 2 devices
[   40.243867] created bitmap (14 pages) for device md5
[   40.244684] md5: bitmap initialized from disk: read 1 pages, set 0 of 28614 bits
[   40.245376] md5: detected capacity change from 0 to 1920248840192
[   40.248331]  md5: unknown partition table
mdadm: /dev/md/5 has been started with 2 drives.
Success: assembled all arrays.
done.
[   40.260413] device-mapper: uevent: version 1.0.3
[   40.260540] device-mapper: ioctl: 4.27.0-ioctl (2013-10-30) initialised: dm-devel at redhat.com
done.
Begin: Running /scripts/local-premount ... [   40.265067] PM: Starting manual resume from disk
done.
Begin: Will now check root file system ... fsck from util-linux 2.25.2
[/sbin/fsck.ext4 (1) -- /dev/md1] fsck.ext4 -a -C0 /dev/md1
root: clean, 44775/122160 files, 265568/487936 blocks
done.
[   40.296866] EXT4-fs (md1): mounted filesystem with ordered data mode. Opts: (null)
done.
Begin: Running /scripts/local-bottom ... done.
Begin: Running /scripts/init-bottom ... done.
[   40.350701] systemd[1]: systemd 215 running in system mode. (+PAM +AUDIT +SELINUX +IMA +SYSVINIT +LIBCRYPTSETUP +GCR
YPT +ACL +XZ -SECCOMP -APPARMOR)
[   40.350843] systemd[1]: Detected virtualization 'xen'.
[   40.350920] systemd[1]: Detected architecture 'x86-64'.

Welcome to Debian GNU/Linux 8 (jessie)!

I still think there must be an issue here as I can see no reason why
udev should not have incrementally-assembled this array on later
appearance of the drives.

Anyway, it seems there is some discussion of this on linux-raid now:

http://marc.info/?l=linux-raid&m=147935582503112&w=2

so I will continue working through it there.

Cheers,
Andy