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I built a linux (Ubuntu) box a year ago and decided to have some fun and use a soft RAID 5. I followed the instructions here.

Things seemed to work fine, but now it's time to reformat the computer and start with the newest version of Ubuntu.

I get to the partition part of the install and run into problems. The system sees my RAID 5 (md0), I just can't seem to get it to reformat that raid.

I have 3 1TB drives (so I get 2TB of storage). All 3 are raided up. First off, is that ok? Having all my drives in the same array (including the boot). It seemed silly to me to raid a block of drives but not have the boot drive raided, because then if the boot drive failed the RAID would be dead anyway. Or is that thinking wrong? I ask because the tutorial I linked to said the /boot drive has to be on a type 1 array.

During the partition portion of the installation, the only thing I can find to "delete" the raid is an option to erase the raid. The next screen says that random bits will be written to the drives and the RAID will be gone. I'm guessing this process could take some time, but I started it 30 minutes ago and it isn't even reporting as being 1% done.

Is there an easy way to just delete the RAID partition, then recreate the RAID (I don't need the drives erased, just a quick reformat would do).


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Until the system boots, there is no way to read from a RAID 5 volume. So it is not possible to boot from a RAID 5 partition. However, a drive can have one partition that's part of a RAID 5 array and one partition that's not. – David Schwartz Oct 25 '11 at 2:13
That makes sense, but somehow Ubuntu does it (I don't really get it, it must do something behind the scenes). I've got the system running and the only drive is the RAID array. What is the "right" way to install an OS and then have most of the system on a RAID array? Partition a little piece of a drive for the OS then RAID everything else? – Tyler DeWitt Oct 25 '11 at 2:29
I would partition all drives the same. Leave a small partition out of the RAID 5 array. On one (or two drives if you want to mirror) use the small partition for the boot. – David Schwartz Oct 25 '11 at 3:02
Sorry, you're right. The drives have to be partitioned the same for the RAID 5 (they are all identical drives). Thanks! – Tyler DeWitt Oct 25 '11 at 3:12

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