JBOD in Debian 4.0

[sebmaster]

Hi,

Im building a Debian fileserver and have installed a basic system and Webmin.

I am now trying to add 2 500Gb HDDs via a SATA PCI controller.

The drives are recognised fine by Debian and I can see them in Webmin (unformatted) however when I go into the "Linux Raid" module I recieve this:

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The kernel RAID status file /proc/mdstat does not exist on your system. Your kernel probably does not support RAID.
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Can anyone tell me howto set up these disks so they appear as one so I can format/share etc?


Also, I think the main drive my OS is installed on is a little temporamental, is there a very simple way of just 'copying' it to another drive, so I can simply swap them and boot as normal without reinstalling?

Thanks!

[TheBigPhish]

Is your kernel capable of SATA drives & RAID capabilities? Which kernel are you using? A home-rolled one or a stock one off a CD?

[sebmaster]

I can see both the drives in Webmin so the kernel supports SATA. Im not sure about RAID though I cant find a definitive answer on Google.

The kernel was installed straight off the CD I havnt modified it.

[IsaacKuo]

Are you trying to use hardware RAID or software RAID? I'm not familiar with hardware RAID, but if you want to use software RAID you'll want to install "mdadm" with "apt-get install mdadm".

I recently transfered over a bunch of Debian installs from one hard drive to another, and learned a LOT about it because there are things that I got away with in Debian 3.1 which are "gotcha" problems in Debian 4.0. It can be very frustrating to troubleshoot, so ask me if you have any problems! (Actually, I'm about to go away on a trip soon, so...well...you can search for IsaacKuo's posts on linuxquestions.org, and maybe get some good info from my WARNING post about moving/deleting swap).

Ahem. Anyway...I moved my server from a pure "normal" partition setup to a combined "normal" OS partition along with software RAID for my main data partition. I did the following steps:

1) Used the Debian installer to create the new partitions, including the RAID data partition. I installed a dummy "disposable" OS partition.

2) I copied the "disposable" OS's /etc/fstab for the RAID partition entry.

3) I copied over the "disposable" OS partition with my old server OS partition using a liveCD (Knoppix). This involved "rm -fvr /media/hda1/*" to first delete the old OS's files, and copying over the OS partition's files with "cp -vax /media/hdb1/* /media/hda1/"

4) I edited the new OS's fstab entry with the RAID partition entry.

5) I rebooted and crossed my fingers...

6) The RAID partition was unable to mount! Ouch!

7) I used "apt-get install mdadm" and crossed my fingers...

After rebooting, the RAID partition mounted! Yippee!

Now, this process was simplified by the fact that I was moving my OS from an old hda1 to a new hda1. If you're moving from hda1 to sda1, then you'll have to edit that also--not a problem, exactly, but you might have some issues with GRUB. Still...there's a sticky on JustLinux in "How I did it!" about installing GRUB which shows how to do that.

But things get really ugly if you have a swap partition.

The problem is that by default, Debian 4.0 will try to resume from swap, and the swap partition is coded into initrd. So, let's say your swap partition is /dev/hda2. Then, upon booting up, swsusp will look for /dev/hda2 and hang if it doesn't exist. You can't even boot up in single user mode! I figured out one workaround, but after my vacation I'm going to see if you can work around it with a "NORESUME" option in GRUB.

[sebmaster]

Brilliant, all working now, thanks IsaacKuo