Expert install - mdadm broke between Wheezy and Jessie

[Kikazaru]

I have a complicated setup, so I need to do an expert install. My UEFI motherboard has an Intel RST chip on it for software RAID, what they also call "Intel Matrix Storage Manager" (imsm), for which Intel provided support for mdadm[1]. I have two SSD drives in a RAID 0 array, and installing Debian onto that array requires some manual intervention. The Debian installer doesn't automatically install the RAID kernel modules, so I have to do that manually, and then manually start up the arrays.

I have successfully installed Debian Wheezy onto such an Intel software array, using the Debian GNU/Linux 7.8.0 "Wheezy" - Official amd64 CD Binary-1 20150110-14:43 image on a USB stick. Reducing the process to the relevant details, I first create the array in the Intel RST OROM, labelled "Boot". Then, I reboot, loading the Debian installer from the USB stick (in UEFI mode), choose Expert Install mode, and run through the first few steps of the installation, up to and including "Detect disks", with no problems.

After detecting disks, I switch to the console, and use the mdadm tool to assemble the array I created in the Intel RST OROM. First, I modprobe raid0 (which also loads md_mod), then run mdadm to assemble and start the arrays.

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~ # modprobe raid0
~ # mdadm --assemble --scan
mdadm: Container /dev/md/imsm0 has been assembled with 2 drives
mdadm: Started /dev/md/Boot_0 with 2 devices
~ # ls -l /dev/md
[...]
[...] Boot_0 -> ../md124
[...]

So, mdadm assembles and starts the Boot array, as it should.

I can then switch back to the installer and proceed with the rest of the steps, continuing with "Partition disks", which lists the RAID array and lets me do what I need to do with it. At the end, of course, I can boot into Debian.

However, something seems to have changed (broken?) with the Debian GNU/Linux Jessie-DI-rc1 "Jessie" - Official RC amd64 CD Binary-1 20150109-01:06 image. I follow the same steps, up to switching to the console after detecting disks. But then, when I call on mdadm to assemble and start the arrays, it merely assembles them; and even though it claims to have assembled "/dev/md/imsm0", no such device exists.

Code: Select all

~ # modprobe raid0
~ # mdadm --assemble --scan
mdadm: Container /dev/md/imsm0 has been assembled with 2 drives
~ # ls -l /dev/md
ls: /dev/md: No such file or directory

Things I've tried:

* Checked if perhaps raid0 or mdadm modules were already loaded before manually loading them. They are not.
* Checked if modprobe raid0 wasn't also loading the md_mod module. It is. md_mod is also loaded.
* Tried appending `--run` to mdadm command: `mdadm --assemble --scan --run`. Output is the same and no devices seem to be created.

No matter what, the RAID arrays aren't started. The Debian installer does not find the array when I go to the next step, to partition.

It took me a long time and a lot of trial and error to get Debian to install on an Intel software RAID, so I'm pretty bummed that now it seems to have broken, somehow, or my method stopped working, for some reason that is beyond my understanding. Does anyone have some idea what's wrong?

[1] http://www.intel.com/content/dam/www/pu ... -paper.pdf

[Bulkley]

If it Stable installs and Testing does not, stay with Stable. Seems obvious.

What I would do is redo the Stable install. Work with it for a few days to make sure everything works properly. Then I would plug in another harddrive and, using Clonezilla, clone the whole drive. That gives you a total backup. Remove the clone drive and save it. Now you can play. I'd try changing my sources list and do a apt-get upgrade. Accept the manager's preferences. If it doesn't work, re-clone your drive so that you have an operating system, back where you started. You can do this as many times as you need until you get what what you want.

[Kikazaru]

Right. I have done that already (installed Wheezy and dist-upgraded). That is a palliative. I'm looking for a real solution to what is wrong with the Jessie installation.

Here's an update. Ran both installs, using --verbose output on mdadm. Here's relevant output from Wheezy:

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~ # mdadm --assemble --scan --verbose
mdadm: looking for devices for further assembly
mdadm: /dev/sdb is identified as a member of /dev/md/imsm0, slot -1.
mdadm: /dev/sda is identified as a member of /dev/md/imsm0, slot -1.
mdadm: added /dev/sda to /dev/md/imsm0 as -1
mdadm: added /dev/sdb to /dev/md/imsm0 as -1
mdadm: Container /dev/md/imsm0 has been assembled with 2 drives
mdadm: looking in container /dev/md127
mdadm: found match on member /md127/0 in /dev/md127
mdadm: Started /dev/md/Boot_0 with 2 devices

And here's what I get from Jessie:

Code: Select all

~ # mdadm --assemble --scan --verbose
mdadm: looking for devices for further assembly
mdadm: /dev/sdb is identified as a member of /dev/md/imsm0, slot -1.
mdadm: /dev/sda is identified as a member of /dev/md/imsm0, slot -1.
mdadm: added /dev/sda to /dev/md/imsm0 as -1
mdadm: added /dev/sdb to /dev/md/imsm0 as -1
mdadm: Container /dev/md/imsm0 has been assembled with 2 drives
mdadm: cannot open device /dev/md/imsm0: No such file or directory

[Bulkley]

The major difference between Wheezy and Jessie is systemd. That's where I'd look for your problem. I plugged mdadm systemd into StartPage search and got About 6,350 results including Does systemd work with mdadm? That one uses Gentoo so this is not a Debian specific problem.

I'm sure there is a solution but I don't know it. I tried Jessie a while back and found it wanting so I reloaded Wheezy and will wait until some of the bugs are fixed.

[Head_on_a_Stick]

I'm looking for a real solution to what is wrong with the Jessie installation.

The jessie installer is still a beta release -- please report this as a bug to enable the Debian team to work on a fix for the Stable release.

[Kikazaru]

The jessie installer is still a beta release -- please report this as a bug to enable the Debian team to work on a fix for the Stable release.

I will do that, then.

Still hoping maybe some saviour here will reveal some insight.

[Kikazaru]

The major difference between Wheezy and Jessie is systemd. That's where I'd look for your problem. I plugged mdadm systemd into StartPage search and got About 6,350 results including Does systemd work with mdadm? That one uses Gentoo so this is not a Debian specific problem.

I'm sure there is a solution but I don't know it. I tried Jessie a while back and found it wanting so I reloaded Wheezy and will wait until some of the bugs are fixed.

When I successfully installed Wheezy, I upgraded it to Sid, including systemd, and have had no problems with mdadm working with systemd. In any case, I don't think the installer uses systemd.

[phys1ks]

I'm also having this same issue with the Intel IMSM... I have yet to find a work around, Debian Jessie 8.2.0

Has anybody had any more luck with this?