Quick and to the point: the software RAID, despite booting properly and having everything appear to work, is useless. I disconnected the second disk in the RAID1 array and the OS refused to boot. I have no idea why. I think this has gone far beyond frustrating at this point. If I’m left with a RAID1 system that can’t even boot if a disk is missing then there’s no point having it the first place and I want my 250GB back.

My next step will be, having convinced the owner of the system to try out a proper hardware RAID card, to see if a hardware RAID1 will overcome these problems. I’ll have to look into it some more first of course and I’ll see if I can work out what is going wrong with the software implementation.

I also promise that not every post in the future will be about RAID!

UPDATE: A new plan has been formulated! I’m going to attempt separating out the /boot partition from mdadm’s clutches and then using rsync to make sure that both /boot partitions on each disk are kept in sync. Let’s see if that works.

The saga continues! Well, after looking into software RAID on Linux everything pointed to me having to install the system all over again. I tried to find an easy way of using the existing partitions (such as by setting up the secondary disk as a RAID device, copying the partition data from the primary disk, then formatting it, adding it to the RAID device and finally rebuilding the RAID) but that was going to be a lot of hassle with no guarantee of success. So I decided to just bite the bullet and reinstall with one of the Ubuntu alternate install discs.

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Continuing on from the previous post, I have looked into various ways of achieving the RAID1 functionality that I need. After browsing some information on RAID on Linux, it seems that the reason the hardware RAID didn’t want to work is that it’s not actually a hardware RAID. The Intel Matrix Storage chipset requires that the operating system have drivers installed that handle all of the actual work involved in running a RAID (which is why these types of RAIDs are called “fake raids”). I believe these drivers do exist for Linux but they’re a pain to set up.

So, following that I looked into LVM, the Logical Volume Manager, as from my shallow understanding of it I believed that it would do what I wanted. Turns out I am slightly wrong in that respect. What LVM really does is allow for partitions to be spread across multiple physical disks and for those physical disks to change without affecting the virtual disk images that all your data is stored on. (For example, you could add more disks to semi-dynamically increase the size of your /home partition.) LVM is also a pain to set up from what I’ve seen and cannot be used as a boot partition. So it doesn’t handle RAID-like functions in the way I’d thought.

I did discover that there are softwares available to handle a “software RAID” on Linux, similar to what the “fake raid” drivers would achieve, without a lot of the hassle. The one I found, mdadm, actually creates “RAID” functionality by combining multiple partitions into a single virtual partition. This increase the flexibility slightly as you don’t need to have a set of identical physical disks. (Also of interest with mdadm is that it seems to have been written by someone from the University of New South Wales – go Aussies!)

I’m going to see how this new method goes tomorrow!

Today I had the fun task on installing Linux onto a Dell Dimension E520. I chose Ubuntu as a distribution for it’s ease of use and, given Dell’s recent commitment to selling Ubuntu on their computers, I thought it would be a safe bet for things like hardware compatibility. It turns out I was slightly wrong about both of those things, at least as far as the installation went.

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