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I'm trying to setup my own (home) NAS. I don't want RAID, I want to use a more flexible form:

  • Mix and match harddrives (now I have 4x 2gb, but for sure when I upgrade I don't want to buy 4 new ones at the same time)
  • Some form of duplication (not backup, but something safer than JBOD)
  • Duplication of selected folders

I've tried Windows Server 2012 R2 with Stablebit Drivepool (looks very good and works simple). Now I also want to try it with Ubuntu but I have a hard time finding out what kind of software is available for this?

I saw Greyhole (but has a bad review: http://zornsoftware.codenature.info/blog/why-i-ditched-raid-and-greyhole-for-mhddfs.html)

Any other ways to do this? Or applications?

RvdK
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1 Answers1

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You should use LVM and a cloning cron script.

I am going to assume this setup for you:

  • 4 drives for LVM and file storage.
  • External USB drive for backups. (at /dev/sdf1)
  • No duplication -- use dd to completely clone as necessary.

LVM

You need to first set up LVM. This diagram is a good example:

enter image description here

Use a hard drive, and assign each to a LVM folder such as /lvm or whatever. This article is very good for describing LVM. I recommend reading it for a better and more detailed LVM introduction.

First off, partition all storage drives, but do not add a partition scheme! Use unallocated as the partition type. I will assume that your storage partitions are /dev/sdb1, /dev/sdc1, /dev/sdd1, and /dev/sde1. Your installation will be at /dev/sda1.

Next, you need to make the drivers LVM-ready:

pvcreate /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1

Once that is done, you want to group those drives:

vgcreate homeNAS /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1

This creates a group called "homeNAS" that conains all of the above drives.

Next, create the Logical Volume:

lvcreate --name share homeNAS

Create the filesystem:

mkfs.ext3 /dev/homeNAS/share

Once this is done, run the following to create the lvm folder:

mkdir /lvm/

Mount it using:

mount /dev/homeNAS/share /lvm

To mount it on every boot, add the following to the end of your /etc/fstab. Make a backup!!

/dev/homeNAS   /lvm     ext3       rw,noatime    0 0

Note that the above guide for LVM is very basic, and is not meant for fancy things. Read the linked article for a much more detailed explanation.

Cron Script

First off, get an external disc drive. It should be plenty big for storing all of your files. It should be able to hold 1.5x the size of your entire LVM partition (ie, 500GB HDD = 750GB backup).

I will assume your drive has one partition (ext4 at /dev/sdf1, which is mounted at /media/backup)

Create a shell script named lvm-backup.sh in /etc/lvm-scripts/ like this:

cp /lvm/folder1/ /media/backup/lvm/folder1
cp /lvm/folder2/ /media/backup/lvm/folder2
cp /lvm/folder3/ /media/backup/lvm/folder3
cp /lvm/folder4/ /media/backup/lvm/folder4

What this'll do is copy the specified folders to the backup drive. You should not clone directly, as that takes forever and can be detrimental to your system.

Quickly run:

chown root:root /etc/lvm-scripts/lvm-backup.sh
chmod +x /etc/lvm-scripts/lvm-backup.sh

To run the backup nightly at midnight, add this to your /etc/crontab:

00 00 * * * sh /etc/lvm-scripts/lvm-backup.sh

If you want more specific control of when to run the script, see this Howto on Cron.

Community
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Kaz Wolfe
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    Thanks for your information. I've just looking into LVM and what I see that if one device fails in the LVM group, the whole group fails. So that will mean that I have to setup 2 drive dedicated for LVM and 2 for backup. If that's the case I can better use RAID (I think). I'st there something flexable where I can say: I have 4 drives, 8 tb total. And I want folder x,y,z duplicated. This will mean that I'm very flexable how I use my storage and don't have it set in stone 2 drives for that and 2 for this. – RvdK Oct 08 '14 at 11:15
  • The nice thing about LVM is you can disassemble/reassemble the system and change it at any time. You can add/remove LVM part drives easily. So, if a drive is pre-fail, just remove it from the LVM group and re-assemble it. That's really the only problem with LVM, you need to be observant to things happening. – Kaz Wolfe Oct 08 '14 at 17:23