Testing a VDO volume and reviewing the stats

In order to test deduplication and compression, we will test with a big file, such as the RHEL 9 KVM guest image or the installation ISO available at https://access.redhat.com/downloads/content/479/ver=/rhel---9/9.0/x86_64/product-software.

Once downloaded, save it as rhel-9.0-x86_64.iso and copy it four times to our VDO volume:

cp rhel-9.0-x86_64.iso /mnt/vm1.iso
cp rhel-9.0-x86_64.iso /mnt/vm2.iso
cp rhel-9.0-x86_64.iso /mnt/vm3.iso
cp rhel-9.0-x86_64.iso /mnt/vm4.iso

This would be the typical case for a server holding VMs that start with the same base disk image, but do we see any improvement?

Let’s execute vdostats --si to verify the data. Note that the image downloaded is 8.5 GB, as reported by ls –si. The output obtained from vdostats --human-readable is as follows:

 Device                Size     &...