With the introduction of OCFS2 1.4 within Oracle VM 2.2, Oracle VM 2.2 has the ability to thin provision your files within your OCFS2 filesystem via the use of the sparse files. One might ask, what exactly is a sparse file? A sparse file is a file that attempts to use filesystem space more efficiently by effectively only using the space required to fit actual data. For example, imagine I have a System.img file within my Oracle VM repository that is 6.2GB in size as seen here:

[root@ovm]# ls -llh System.img
-rw-r--r-- 1 root root 6.2G Apr 14 09:18 System.img

If I did not have the sparse file feature within my Oracle VM 2.2 operating system, the  System.img file would actually take up 6.2GB of allocated space away from my OVS repository. However, with the introduction of sparse files to OCFS2 1.4, the actual data contained within  my System.img  was only 3.3GB as shown below. A total savings of 47% of actual diskspace!

[root@ovm]# ls -lsh System.img
3.3G -rw-r--r-- 1 root root 6.2G Apr 14 09:18 System.img

Now that we understand the huge advantages of enabling sparse files, I will show you how to enable sparse files for your Oracle VM 2.2 environment.