loopback block device for backups

BeZazz · Post #1 (**permalink**) 05-22-2011, 04:56 AM

Here is a post I just made at another forum.

Quote:

Brief overview of my issue.

Live server with not enough free space for backups except on /home partition. Place backups there and quota wont work.

What I currently do is run a script after cPanel does backups that copies the backups to 2 off site servers.

I would like to keep a copy of the backups on the original server and also have quota enabled.

Is it possible to create a loopback back device from some of the space on the /home partition?

Thanks

Is what I am thinking possible?

Thanks

othellotech · Post #2 (**permalink**) 05-22-2011, 04:50 PM

Just ask your server provider to install another drive

BeZazz · Post #3 (**permalink**) 05-22-2011, 09:48 PM

The server is actually collocated. It is in the US and I am in Australia. While adding another drive isn’t out of the question I would much rather use the space that I already have.

depictedminds · Post #4 (**permalink**) 05-22-2011, 10:32 PM

Did you want to make a file (like a .img file) which is on the home partition, with a given size, and mounted in a location (for pure example, /home/backups)?

Straight up, I cant say I am really good at this stuff - but I did have a look at a website :

http://mykospark.net/2011/04/create-...stem-in-linux/

Im aware that this just basically explains how to make a loopback filesystem in linux - but would this apply in your situation?

I'd personally be interested in knowing - while I dont operate cpanel, I use DA, this would be interesting to know.

BeZazz · Post #5 (**permalink**) 05-25-2011, 09:36 PM

Thanks for the reply mate.

I just came back to post what was done regarding this then saw the post above(thought I would have received an email)

On the other forum where I posted a user " YUPAPA " answered all my questions and provided everything I needed he/she basically spoon fed me which I am grateful for.

Bellow I will paste the code I used as provide to me with no changes.

Quote:

You can do the following to create a 5G backup disk
dd if=/dev/zero of=/home/backupdisk.img bs=1M count=5000
losetup /dev/loop0 /home/backupdisk.img
mkfs.ext3 /dev/loop0
mkdir /backup
mount /dev/loop0 /backup

Use another loop device if loop0 is in use. losetup -a to list all occupied devices.

If you don't need the disk anymore:
umount /backup
losetup -d /dev/loop0
rm /home/backupdisk.img

fstab

Code:

/home/backupdisk.img          /backup                    ext3    defaults,loop   0 0

It all appears to be working for me

but I am yet to reboot the server, so I can not be 100% sure the image will auto remount.

idologic_dh · Post #6 (**permalink**) 05-26-2011, 08:21 AM

That looks fine to me, but the performance during backups would drop more significantly since you are writing to the same disk. If you can do add a 2nd drive.