I am trying to set up a simple but effective solution to make a backup of my rackspace cloud servers. These servers each run subversion, trac, and some database-backed custom php applications.
My idea is to set up a LVM and mount a volume under, say, /srv. In this volume, I keep the data from all applications. Instead of caring about how to back-up each app in a different way (svn hotcopy, trac-admin hotcopy, huge mess for mysql), I simply take an LVM snapshot and back this one up cloud files using the excellent cloudcity script (http://github.com/jspringman/cloudcity/blob/master/cloudcity).
The advantage of this solution is that it is quick and easy, and LVM allows to make decent backups. As more apps are added, it should not be required to change the backup script much.
The downside, and main point of my question here, is that I am not sure how to get LVM working on Rackspace cloud, because there is only one root volume and no service like Amazon's EBS. I was thinking it may be possible to create a large empty file and use this as a "physical volume".
Has anybody done anything like this before? Or do you know why it can never work? It would be great to hear from you.