I'm protecting about 130 Hyper-V VM's with a DPM 2012 R2 server. However, I'm soon running out of volumes so I need to co-locate this data. It's quite simple with SQL data as this is configurable in the PG properties, but where do I enable this for Hyper-V data? Is it possible to co-locate data already protected as non-colocated data?

/Amir

DPM supports co-location of HV data. Co-location can be enabled when you create a protection group. I did not try it myself, but I believe you can co-locate existing data by removing your HV source from non-collocated protection group with "retain data" option and then adding the source to a new, co-located group.

You should also change co-location options in registry to match your requirements:

DSCollocationFactor  - number of VMs per co-located volume

CollocatedReplicaSize - size for co-located replica volume

 See Colocate data from different protection groups on disk for more information

As Gleb pointed out please refer to the below link for details on how you can enable co-location of hyperV VMs

https://technet.microsoft.com/en-us/library/jj628128.aspx