Comments on: Software RAID-5: using mdadm in Ubuntu 9.10

By: Jamie

Jamie — Tue, 27 Jul 2010 11:12:38 +0000

This guide is assuming you are using the array to store media or something other than the OS on it. As you’ve read, storing /boot on a software RAID partition wont work – since the RAID is done in software it wont be constructed/mountable at the time /boot is needed.

By: AndyS

AndyS — Tue, 27 Jul 2010 04:00:40 +0000

am i missing something, this seems to be what I want to do, but what I had been reading said that /boot could not be in the raid5 array.

I really hope this is not the case.

Wanted to build a 10.04 ubuntu server with 3 disks in raid5 with a 4th waiting as a spare

By: Dennis

Dennis — Tue, 11 May 2010 13:58:34 +0000

Thanks for the clarification

By: Jamie

Jamie — Fri, 07 May 2010 12:16:38 +0000

Yup mine says the same, as far as I’m aware it’s normal and nothing to be worried about.

By: Dennis

Dennis — Fri, 07 May 2010 11:37:14 +0000

Jamie,

Thanks for the great tutorial. Written in a very informative and concise manner. Managed to get my raid 5 with 3 x 1.5 WD Caviar Green drives up and running. Only issue was that after all the resync and create ext4 partition, I ran fdisk -l to check the array and the message showed no valid partition on md0.

Was worried that this will come back and haunt me in the future and tried to search for a solution thru the web but found most people saying that this is normal.

Do you have the same message as well in your system?

By: Mike

Mike — Tue, 16 Mar 2010 06:21:50 +0000

Great tutorial! Worked like a charm for me. I only used the steps from ‘Creating the array’ and on. I first formatted my drives with GParted. The 5% reserve was included when I first formatted my three hdds. My RAID is all set and running. Is there any way I can get rid of the 5% reserve on each individual hdd without having to rebuild the entire RAID? These are 1.5TB hdds. It took about five hours to build and I would like to skip the process if possible. Any help is greatly appreciated.

Thanks, Mike

By: Doug

Doug — Mon, 15 Feb 2010 03:04:20 +0000

Don’t worry about the drives falling out. From what I have read that does not affect mdadm, and is an issue with hardware raid cards.

Managed to return my WD Green’s and exchange them for the Seagate 11′s now I am having no problems. Cheers for the info, it was a relief to know what drives could actually work.

You might like to look into tweaking your file system for raid 5 too.
http://www.linuxfoundation.org/collaborate/workgroups/linux-raid/raid_setup#Options_for_mke2fs

By: Jamie

Jamie — Fri, 12 Feb 2010 20:22:06 +0000

Not yet *fingers crossed*. I’m now actually running a total of 6 drives in the array, haven’t had any problems yet…

By: Doug

Doug — Fri, 12 Feb 2010 20:19:52 +0000

Have you had any issues of the drives falling out of the array? Reading the reviews at NewEgg some have experienced drives falling out with the Seagate’s.

I have been trying to do exactly the same setup as you with the 1.5TB WD Caviar Greens but they just do not work in RAID. One drive always falls out at build time.

By: Jamie

Jamie — Fri, 12 Feb 2010 20:01:51 +0000

Thanks for the replies

@indu: Yes it is. If you don’t want to lose the data on the existing drive you can create an array in degraded mode using just 2 drives, then copy your data over, then add the third drive to get it out of degraded mode back to normal. I’ve never done it though so I can’t help with how sorry.

@Doug: I used 1.5TB Seagate Barracuda 7200.11 drives, but if I was looking to do it now I would probably go with 1.5TB WD Caviar Greens.