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I am a linux noob and have been saddled with a problem far beyond my abilities.

My situation is this:

  • This box: http://www.soyoustart.com/us/offers/bk-24t.xml (6x4TB drives)
  • OVH image based install of Ubuntu 14.04 server - I do not have access to installation as I would if I were installing from DVD. I tell the CP what OS I want installed and it returns an installed system based on their configuration. I do have some options, one of which is use distribution kernel. I can also choose a partition scheme via the web but it only exposes the first drive. I can choose to install all on one disk which would put /, /swap and /home all on that first disk.

  • RAID info after their OS install: http://pastebin.com/hGnK9Znp (Asking in the official #ubuntu channel I am told that: "that's 1 disk with 5 mirrors and zero spares. It has 5 allocated mirrors - it's a very bad config".) Edit: Is it possible they have just screwed up when setting up the raid? Could it just be down to human error on their part?

Desired Outcome:

  • Raid1 system and swap disk Do I have to allocate a whole disk to this or can I use part of one? Sys and swap will never need 4TB will they? As I understand it, and if a whole disk is used, this would be 4Tb storage and 1 drive redundancy (eg a mirror of that drive).

  • Raid5 for the remaining 4 drives as one big volume on which /home lives. As I understand it, with raid5 this would provide 12TB of storage and single drive redundancy.

Obstacles

  1. I am not a linux geek

  2. I am unable to alter the way the OS is installed. I do have a 'recovery mode' which loads an image via the net and allows me to work with the various systems on the installed OS. I can, for example, run parted but apt-get doesn't work.

  3. I have no idea how to get from the RAID array listed above to the config I have described.

  4. I am stuck with this server and this provider.

Complete loss of data is fine if I end up where I need to be.

I have looked at some official documentation but it seems out of date or is otherwise inapplicable. Specifically these resources:

  • help.ubuntu.com/community/Installation/SoftwareRAID
  • help.ubuntu.com/community/FakeRaidHowto
  • www.tldp.org/HOWTO/LVM-HOWTO/

Edit 2: The advice I got from #Ubuntu is: "basically, break the 5 mirrors, create new raid 5/6 array out of them, that is it (if you don't want to touch the root disk). Once thats done, remove the remaining 1 disk raid 1 out of raid configuration as there are no more mirrors for it, you need to remove it. I advise you to mark the 5 mirrors as "failed" before removing them so it thinks the disks have failed before you disable them.

While that makes sense conceptually, the practical application of that advice is beyond my current understanding.

I've tried to be comprehensive in describing my problem, but I am sure I have left salient details out. Please ask for clarification where needed.

Thanks :D


Update 2014.09.05 I have re installed the OS using the Custom Installation option and the Install Entirely On First Disk option in the partition scheme dialogue. This leaves the remaining drives completely untouched. This means I should be able to set them up as a new raid array instead of having to undo the default raid array as installed.

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The short answer:

Using ovh's CP choose reinstall and tick custom install. Select Install all on first disk. Install.

Log in as root and the other drives are completely unallocated. You can act on them as you would any other drives and there is no pre-installed raid to overcome.

Also, I decided to go with backups over raid 5 or 6 after reading about the odds of a volume failure after a drive failure. See: http://www.datamation.com/storage/data-storage-the-myth-of-redundancy-1.html

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