RAID 0 Setup Guidance Help

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RAID 0 Setup Guidance Help

Postby Jim7060 on Mon Feb 04, 2013 11:47 pm

Hi everyone.

Ok - So, I've been reading up on similar questions, situations and solutions, and have attempted to mod them to fit my situation but my Linux knowledge is still limited and i'm unable to create a RAID 0 array for this setup. I come to you all tonight after four days of failing to get this new machine a RAID 0 array.

The Machine [Custom Built]:
Corsair Obsidian 550D
ASRock Z77
Intel Core i5 2500k
16 GB DDR3 1600MHz
GeForce 660 GTX
x5 3TB WD RED HDDs
x1 256GB Samsung 840 PRO SSD
Linux Mint 14 Maya 64-bit [Cinnamon]

The goal is to make this computer my home media server to stream movies and music and possibly games (a tricky one) around the home network (servicing 3 computers running Windows 7, a Mint laptop, 3 Android phones, and the occasional iOS device). For this to happen i'm trying to get the five 3TB HDDs into a RAID 0 form, while the SSD serves only as an OS drive & temporary download storage medium (off of the array). I've dabbled in GParted (changing all the drives to GPT), Terminal (killing my 'sudo' keys before learning 'sudo su'), and mdadm (typing --help quite frequently) to get this thing working, after killing the fstab file eventually forcing a format, I decided it was time to seek professional help.

I know it's not hard at all...

Thank you in advance.
Jim7060
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Re: RAID 0 Setup Guidance Help

Postby milius on Wed Feb 06, 2013 6:28 am

What exactly doesn't work?

Did you try to manually assemble the array?

This isn't really aimed at mint, but you should be able to find a lot of hints there anyway:

edit: oops, wrong link. This one should a less specific point to start out from:
https://wiki.archlinux.org/index.php/RAID
(.. than this one https://wiki.archlinux.org/index.php/So ... ID_and_LVM)

You might also want to look into alternatives if you haven't already... like LVM or raid5... also there are a few filesystems that could do the trick for your purposes (...possibly better / easier / more flexible than mdadm? p.E. btrfs), but I haven't tried any of those yet.
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Re: RAID 0 Setup Guidance Help

Postby Jim7060 on Thu Feb 07, 2013 1:14 am

I get as far as creating the array through mdadm and editing the fstab file.

And i'm hitting quite a few walls:
1. After creation, I try to do read/write to this new volume (as it appears mounted just after the creation and initialization), it won't let me and upon inspection it is saying that i'm not the owner and thus do not have a way to edit the files on the volume.
- I'm thinking it's a 'ch' problem.
2. While mounted, the volume appears in the tray as a removable device?
- Not a big issue and something I can live with, but it bugs me as these are all internal separate HDDs.
3. I umount the volume (no problems there), but later upon mount, it throws "/dev/md0 doesn't exist".
- Guess that's an fstab issue?
4. Upon reboot, after I messed with fstab, the array was somehow corrupted and I couldn't boot to my SSD where the drive was installed.
- Again, probably fstab...
5. After reboot, if I don't edit fstab (it boots fine), I get into Gparted and it throws lots of errors at me, including could not find /dev/md0 and continues to insult me by saying sda, sdb, sdc, sde all have corrupt GPT partitions (because they're empty?) and that it found a backup partition and will use it...

I have checked out several articles on the fstab file and I while I know what it does, I don't know what it does... if that makes any sense.

After checking out the links that you have provided, I may just jump to an LVM instead if what I'm trying to do is not currently possible... I thought about jumping back to Windows for Server 2008... someone hit me if I think about it again.

I did have a brain surge just a few moments ago:
My motherboard has UEFI, which can boot GPT partitions... so instead of using 5 of 6 drives in the array, I may just drop the 6th (even though it's an SSD) in it; the only question I have on this is what flags would I use on the drives? I read somewhere that both RAID & boot flags cannot be enabled at the same time (doesn't make sense to me). I still would like for the SSD to be independent from the rest of the storage, so perhaps just partitioning it right would work?
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Re: RAID 0 Setup Guidance Help

Postby milius on Thu Feb 07, 2013 4:29 am

First of all...
NOw..:

1) How are you "Inspecting" md0? Have you mounted it somewhere? Does it even have a filesystem on it? Can you write to it as root?
2) Ignore that for now. Automount might do strange stuff.
3) If I remember right, md0 should not stop existing unless you disassemble the array or reboot.
4) There is no need to edit your fstab file and risk ruining your system if you have a seperate boot partition on your ssd. At least not, before you can manually mount your raid device and EVERYTHING is working fine. Also, don't change the existing lines unless you really want to change your existing mounts. I thought you only wanted to *add* a mount? I still don't understand why you mess with your SSD if it's not part of the array.
5) Why are you rebooting / what are you expecting? Also: Sounds like you did something wrong in mdadm.conf. Also you might be (accidentally) trying to boot from raid and have forgotten to add the needed modules or hooks or simply just to regenerate initrd?

. I still would like for the SSD to be independent from the rest of the storage, so perhaps just partitioning it right would work?

I don't understand... I thought the OS was already running on your SSD (which is not part of the array)... and that is supposed to stay that way? Why repartition it / change it / even touch it?


You should provide a lot more information so someone can help you. Like your fstab file, your mdadm.conf, output of the commands while you manually assemble the array and mount it... etc... if you're not getting enough information to figure out what your problem is you're probably not using the tty enough.
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Re: RAID 0 Setup Guidance Help

Postby Jim7060 on Thu Feb 07, 2013 11:06 pm

After I create the new array, it's listed as "15TB Volume". I open it and try to do anything with it, even as root and it won't let me because it says I'm not the owner.

The SSD is simply the place where Mint will be residing, boot, root, home, swap, ect will be on that drive. the 3TB drives are simply a slave storage. It is for this reason in which I now believe a LVM is better for this application... I was modifying the fstab because the guide said to do such lol. The reboot is done after I have completed the setup & configuration, It is just habbit to reboot after I do major changes (thanks Windows...)

I've actually dumped the plan for a RAID 0 array on this system (everything is backed up locally & online anyway) and will be creating a LVM with assistance from this link:
Code: Select all
http://forums.linuxmint.com/viewtopic.php?f=42&t=108442
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