Setup
Before continuing, you should have a RAID 5 array with a State: of Running. You can verify this using the Edit Components button that’s to the right of the State and see the health and status of each individual disk that currently makes up the RAID array. The State for the individual drives should be Fully Synchronized, this indicates that the drives all have current parity information for the other drives.
While you’re here, also note the Add Spare and Expand Array buttons. The Add Spare will not be addressed in this guide, but that function is there if you should ever want to research and use it.
The Expand Array button however, will be addressed below in the Configuration section of this guide.
Formatting the File System
Now, to finish the setup of this RAID array, select your RAID array, and find the Format Volume button. This will pop-up a small window with another drop down box. There are several options available here, however I strongly recommend using the default, EXT4.
Note: EXT4 is the default file system for Linux based operating systems (Ubuntu included). It is the direct successor of EXT3 (the previous default) and will eventually be superseded by BTRFS. It has been out for a few years now, the bugs seem to have been worked out, and it includes many nice features (such as checksumming) when compared to EXT3.
Type in the name for your volume, this can be the same as your RAID array’s name and, again, really doesn’t matter. Make sure Take ownership of filesystem is checked, and unless you know what you’re doing leave Encrypt underlying device unchecked.
When you’re happy, hit the Format button and the array will begin to format with the EXT4 file system (after a likely password prompt). This process will take some time, but should take considerably less time than the initial building of the array.
How would you recommend testing the array? I’d like to make sure it’s capable of recovering from a (staged) single hard disc failure. Could you also tell me how to restore it?
Hi Ian,
This is something I plan to add to my next revision of the guide. Simply shutting down the system and unplugging one of the drives should simulate a failure. From there use the Disk Utility to attempt a restoration. I haven’t played around with this yet so I can’t offer concise advice but I have little doubt it’s straight forward. A virtual machine could also be used for testing as well.
Good luck!
Hey Ian,
Yeah, if you’re wanting to fully restore the array swap out the old drive and swap in a blank one and then add it to the array and restore it.
Take care,
Hello,
Thank you for the excellent guide. I do have a couple of questions which I hope that you might be able to answer for me.
Q1. At what point was Ubuntu installed?
I have followed your guide to the point of formatting the volume. I saw in your comments that you made the following comment:
“That’s right, if you format the array with a file system (Format Volume) you can begin to use the array now, however you will have zero redundancy, and even a single disk failure will cause you to loose ALL of the data on the array.”
On page 4 of your guide you go onto format the volume using EXT4, so I am a little confused.
I’m running an MSI K9N2GM/VM motherboard which has the ability to use the BIOS Raid 5, but following your guide plus a few other guides, I have turned the BIOS raid off.
I’m primarily running the Ubuntu 10.10 live cd, but am going to try again with 10.04 this afternoon.
The main problem I’m running into is that when I come to install Ubuntu, it complains about not being able to decipher the disk geometry.
I would be very grateful for your guidance. Once again, a great guide!
Many thanks in advance,
Jeremy Hannah
Hi Jeremy,
The guide assumes you already have an Ubuntu or Linux Mint operating system installed on a different drive and are using the RAID 5/6 array for archival/storage purposes (not as a boot drive).
I’m not sure what all problems you might run into with using this guide for a boot RAID 5/6 array as I’ve not tested or experimented with that. At very least you’d probably need to back-up your mdadm.conf file and import that into your new system.
At least part of the reason for going with the software RAID 5/6 setup was so that it was independent of the operating system, using the RAID array as the OS boot disk seems to, at least partially, defeat this purpose.
If you have any further questions please feel free to respond or email me directly, I’ll try to help out as best as I am able.
Take care!
daemox
I am following your guide for Linux Mint and would like to setup the RAID 5 for my os. Could you tell me what steps I would need in order to successfully setup a raid 5 instance?
Hi John,
The steps should be very similar.
I no longer run Linux Mint myself so I wont be able to give you a 1:1 guide.
As stated in my guide this really isn’t a novice user’s topic, (especially if problems arise down the line).
Best of luck to you though!
This was an awesome guide. Exactly what I had been looking for. I’ve been having some problems with the drives reporting that they are misaligned by XXXXXX (3072 bytes this time around) what gives? I have gone through this several times deleting the partitions on each drive and then reformatting the drives in GUID and recreating a RAID5. Can I ignore this, or what should I do different to start all over again.
Hi Hal,
Unfortunately, I’ve never ran into that issue so I’m unfamiliar with it. I’d recommend searching Google/Ubuntu/Linux Mint resources for answers. It may be related to your specific drives, or how they were partitioned. I honestly can’t say though.
Best of luck!
Hi there,
Thank you for this fantastic guide. It was very useful for me. I had a similar issue with misalignment. In my case it was due to the 4096 byte sector size of my 3TB drives. I was able to resolve it by using GNU parted prior to setting up the RAID. I used these instructions: http://www.cyberciti.biz/tips/fdisk-unable-to-create-partition-greater-2tb.html
I hope this helps.
Hi Ozgur,
I’m glad the guide worked out for you! Thanks for the note about the 3TB alignment as well. Unfortunately I haven’t gotten to play with 3TB drives yet so I’m currently unable to help with them. Happy you provided a link, cheers!
Hi :) This is not just an awesome guide. it’s absolutely amazing!! WOW! I’m quite new to Ubuntu and RAID and had absolutely no problem following the very simple but not over simplified steps and have now got 3x 2TB drives working in perfect harmony and auto-mounting at boot. I had Google’d for hours, trawling through complicated out of date guides that made me want to give up and shoot myself, and then I stumbled on this one. I would like to say a gigantic thank you to Daemox for all your time and effort on this guide, you deserve a huge pat on the back :) If anyone is reading this before they try and set up a RAID array and is unsure…don’t be, if I can do it then anyone can :)
Hi Daemox :)
I have a quick question…I recently installed 3x 2TB WD Green HDD’s on an ASUS M4A88T Evo Board with Ubuntu 11.04 running off a 30GB SSD and a SATA DVD drive. The SSD and one of the WD’s are showing up under the SATA controller (Disk utility) and the other two WD’s are showing up under the PATA controller! As I wrote earlier, the RAID 5 seems to work fine (thanks to your excellent guide) but I just wondered if you knew any reason why the two drives show up on the PATA controller rather than the SATA? They all use SATA leads and I haven’t used any jumpers or anything else to change the drives! Would really appreciate any thoughts :)
I have just read and used your XBMC guide too…eternally indebted ;)
Steve
Hi Steve,
I was about to respond to your other comment but I’ll throw it all together here.
Many thanks for the kind words, definitely appreciated. I’ve been a bit busy elsewhere recently, so this helps keep me motivated to keep my guides updated.
As for the controller oddity, it may come down to how your motherboard’s north and south bridge are setup. The two WD SATA drives may be going through a make shift SATA connection that uses the PATA chip on the south bridge to add a couple extra ports to the mother board.
If you’re worried you could use the benchmark utility in Disk Utility to see if there’s any performance impact on those two drives.
Anyway, I hope Ubuntu/Linux works out for you, and thanks again for the comments on my guides.
Best of luck and take care,
Hi, I’m back again ;)
After running my raid 5 array for a while on Ubuntu now I have encountered a whole heap of problems and have decided to give Suse 11 a go. I can see the three 2TB HDD’s and Suse tells me that they were in a Linux Raid, but I’m really unsure of how to re-assemble the array on Suse. The “Expert Paartitioner” seems like the right tool, but I don’t want to go in like a bull in a china shop and lose all the data on the array. Could you possibly point me in the right direction please :) Thanks in advance for any help or advice. Steve
Hi, I’m back again ;)
After running my raid 5 array for a while on Ubuntu now I have encountered a whole heap of problems and have decided to give Suse 11 a go. I can see the three 2TB HDD’s and Suse tells me that they were in a Linux Raid, but I’m really unsure of how to re-assemble the array on Suse. The “Expert Paartitioner” seems like the right tool, but I don’t want to go in like a bull in a china shop and lose all the data on the array. Could you possibly point me in the right direction please :) Thanks in advance for any help or advice. Steve
Hi again Steve!
Unfortunately, I have zero experience with RAID on SUSE. I haven’t even fired up a SUSE install in years. In Ubuntu 11.04 all that needs to be done now is to install mdadm and reboot. From there, the array will auto initialize and can be mounted manually or fstab can be edited to auto-mount it.
Sorry to hear you were having issues, but not sure if a distro hop is the best solution for you.
Cheers, and feel free to bounce ideas off me here or via email!