[...] After reading way too many articles on RAID and mdadm and lvm, I finally came across this article.  This article was definitely a eureeka moment, and within 5 mins I had set up my raid array (not counting the 2hrs of formatting…).  Cool stuff! [...]

I found this guide very quick and easy. Thanks very much for taking the time to write it up

I Have to try this with Ubuntu 6.06 LTS server. I have 4 x 250Gt ATA disk and 160Gt install disk for ubuntu.

Have just done this on Gutsy (Ubuntu 7.10 64bit). Worked fine, thanks a lot. As a tip, I used System->Administration->Synaptic Package Manager to get the mdadm command installed.

Does anyone know how to set up the server to email (or alert another way) for disk failures or array degradation? I have read a few other tutorials but none of them cover proactive disk monitoring.
Thanks,
-Ivan

Found it! http://linux-raid.osdl.org/index.php/Detecting%2C_querying_and_testing#Monitoring_RAID_arrays

Thanks Ivan! I should have probably included something like this.

Guide worked great except my system wouldn’t startup on reboot. I had to use a Recovery Disk to edit out the line in /etc/fstab just so it would boot. It seems there’s one step missing, at least it was required for Fedora 8 x86_64. Anyways. Before rebooting you’ll probably want to:
mdadm –detail –scan –verbose > /etc/mdadm.conf
if you want your system to startup. Like I said could just be a Fedora thing, but I’m betting otherwise. I found this here:
http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:_Ch26_:_Linux_Software_RAID
I also used fdisk instead of cfdisk.

Hi Bando,

That step doesn’t appear to be necessary in Ubuntu – I don’t recall doing anything other than the above. I’ll be doing another raid5 setup in the next week or so with Hardy Heron. I’ll update my findings then.

Anyways, thanks for the comment!

Great howto easiest one I have found. Hopefully someone can take this and GUIfy it for new users.

FYI small typos need fixing

–create*
–raid*
–level*
–chunk*

One dash wont work. Still kick ass article otherwise. Works great in Ubuntu 8.04 and 7.10.

@Paradexes

Thanks, yeah I’ve noticed that but for some reason my wordpress theme gunks out the double dash.

Glad it proved useful nonetheless!

Edit: I fixed the double dash problem in Wordpress

AWESOME! Simple, quick and dirty HOW-TO. Thanks so much.

This might be the same problem Bando Bando experienced above.
I’ve just installed 4 x 1TB in raid5 in Ubuntu 9.04. After reboot – no md0??? I tried mdadm –assemble –scan, and got only 3 disks. Ok, fine, I’ll add the forth then, I thought. I got device or resource busy. Ok, reboot again, then I only have 2 disks, and array can not be assembled of course. I tried a lot of things like clearing the superblocks, re-partioning etc, same problem still, loses one disk each reboot.
In /etc/mdadm/mdadm.conf it says
DEVICE partitions
CREATE owner=root group=disk mode=0660 auto=yes
HOMEHOST
I replaced these lines with
DEVICE /dev/sd??
ARRAY /dev/md0 UUID=1b0816d7:c82651a0:67e26e6e:a4449dba
The UUID is of course mine, you will find yours using mdadm –detail.
Now it works, I don’t know why. Maybe that I on one disk have a small partition with Ubuntu, and on another disk a swap partition, each 10GB, only then this problem occurs? For example I have another computer where I have 8 dedicated disks in raid5, ie Ubuntu installed on a ninth disk, no changes done in mdadm.conf and despite that everything works fine. Hope this can be of help.

[...] Quick and dirty linux software RAID5 | How in the TECH – January 30th ( tags: raid linux howto server raid5 mdadm ) [...]