Installer complains about /dev/md/0p1

[Chris Thompson]

Trying to install Breezy Badger colony release 5 (or preview release from 2005-09-09,
same error in both cases). Using the standard installer, manually partitioning disk.

Inside VMWare workstation 4.5.2 build-8848. One IDE disk set up, four SCSI disks.
Want to stick / and swap on IDE disk, no problem. Want to configure all four SCSI
disks as a single RAID-5 partition, then stick LVM on that.

After configuring all four SCSI disks as software RAID5 in the installer, I go to set
up the RAID5 partition as LVM and then 'Configure the Logical Volume Manager'. I get
the following error message:

[!] Partition disks

Error informing the kernel about modifications to partition /dev/md/0p1 - Invalid
argument. This means Linux won't know about any changes you made to /dev/md/0p1 until
you reboot - so you shouldn't mount it or use it in any way before rebooting.

ERROR!!!

Ignore / Cancel / Go Back

Note that rebooting and restarting the installation gives me EXACTLY THE SAME ERROR
when I go to mark the RAID5 partition for LVM and then 'Configure the Logical Volume
Manager'.

The problem has nothing to do with LVM. If I mark the RAID5 partition as XFS instead,
I get the same error message when I tell the installer that I'm finished partitioning.
It appears that the installer is unable to handle software RAID5 partitions (at least)
and if so, a warning message must be displayed when the user goes to create one.

[Chris Thompson (chris-hypocrite)]

If you ignore the error message and complete the installation with the RAID-5 partition as XFS,
everything works fine for the rest of the install. Additionally, /dev/md0 and my xfs partition
are found and mounted appropriately.

I have not yet tried a similar setup with lvm.

[Chris Thompson (chris-hypocrite)]

It seems as though it works, even with the error message, creating lvm on RAID-5 in the installer
as well. I made sure to double-check /proc/mdstat to make sure that all four drives were a part
of the array.

The error message still comes up, though, so SOMETHING ain't right.

[Colin Watson (cjwatson)]

We seem to be trying to do RAID partitioning for some reason, which I'm told
isn't supported. I wonder why we're trying to do that.

[Colin Watson (cjwatson)]

parted's Linux-specific layer appears to be blissfully unaware that there are
disk types (i.e. loop, used by partman-md for assembled RAID devices) that
contain a partition in parted's internal data structures but which do not in
fact use a partition table or have separate device nodes for partitions. I
believe that this is a bug in parted.

However, if it's basically working at the moment except for the warning, I think
I'm going to leave it as it is for Breezy. Changing parted to make it know to
use just /dev/md/0 etc. could have knock-on effects as far as the bootloaders,
and we don't have time to deal with those consequences before release.

[Colin Watson (cjwatson)]

*** Bug 22273 has been marked as a duplicate of this bug. ***

[anonym (launch-mailinator)]

Faced the same error (trying to install Ubuntu 5.10 on a software Raid level 0 over 2 SATA HDDs).

Changing the Filesystem type to XFS seemed to work once. But I don't know what I did, it stopped working later. Maybe a reboot/reinstall could have solved the problem. But here is a solution.

Strangely, limiting the install partition to a single root partition (without separate /home ...etc) seemed to solve the problem. The packages installed fine, but the boot loaders refused to. Going back and creating a /boot partition outside of Raid (and recreating the / partition) solved the problem.

These steps, if done by the installer, atleast in guided partitioning, will be great.

[Colin Watson (cjwatson)]

Apparently (thanks to Frans Pop) this can be avoided in partman-lvm for the LVM-on-RAID case. The following Debian upload, which is now also in Edgy, solves it:

partman-lvm (41) unstable; urgency=low

  [ David Härdeman ]
  * Remove parted_names since its of no use for virtual filesystems
    (closes: #329765)

  [ Frans Pop ]
  * Major whitespace cleanup in scripts + some minor syntax changes.
  * Sync undo.d/lvm script with init.d/lvm; adds missing hack for RAID devices.
  * As setting flags on RAID devices does not work and causes errors from
    libparted, do not attempt to sync flags in case of LVM on RAID. Partman
    itself does not rely on the lvm flag, but uses the "method" instead.
    This is in line with existing hacks in init.d/lvm and undo.d/lvm.
    Closes: #377391.
  * Remove duplicate depends; add debconf dependency.

  [ Updated translations ]
  * Arabic (ar.po) by Ossama M. Khayat
  * Czech (cs.po) by Miroslav Kure
  * Dzongkha (dz.po) by Jurmey Rabgay
  * Japanese (ja.po) by Kenshi Muto
  * Macedonian (mk.po) by Georgi Stanojevski
  * Swedish (sv.po) by Daniel Nylander

 -- Frans Pop <email address hidden> Sun, 9 Jul 2006 17:48:12 +0200

[Ralph Janke (txwikinger)]

Shouldn't this be backported to Dapper being a LTS release ?

[Ralph Janke (txwikinger)]

Made a mistake

[Martin Pitt (pitti)]

Colin, the applied Debian partman-lvm patch looks straightforward. Does it apply to the dapper version as well? Since the next dapper point release is aimed at servers where a setup like this is more common, it looks like a good opportunity.

[Martin Pitt (pitti)]

Easy and safe to fix according to Colin, just needs testing.

[Colin Watson (cjwatson)]

Uploaded to dapper-proposed.

[Martin Pitt (pitti)]

Thanks, Colin! Accepted into dapper-proposed.

[Martin Pitt (pitti)]

Verification: in VMWare I create a RAID-0 out of two partitions, set the raid volume as usage 'lvm', select 'Configure LVM'.

- On 6.06.1 CD I get the "/dev/md/0p1 - Invalid argument" error.
- On 6.06.2 candiate CD I do not get the error, LVM setup works flawlessly, and the system installs.

Considering verification-done.

[Martin Pitt (pitti)]

Copied to dapper-updates.