Are you looking for this?
Metric Name: Guest file system|Total Guest File System Capacity (GB) This metric displays the amount of disk space allocated for the VM.
Description: Correlate other metrics with this metric to indicate if changes occur in the disk space allocation for the VM. Key: guestfilesystem|capacity_total
No Bro, I am looking data store metric
diskspace | alloc | Usable capacity
The allocation model has been removed that is why that metric is no longer there.
There are 3 new ones
Disk Space|Utilisation (GB) This is the one you are after i think (this is used storage space)
Disk Space|Virtual Disk Used (GB) This is the space used by the virtual disks only (no other vm files)
Disk Space|Virtual Machine used (GB) This is the space used by virtual machines only (All vm files but nothing else eg ISOs)
sorry just read it again it is prob the
disk space|Freespace (GB)
As an addition to the previous posts, have a look at https://docs.vmware.com/en/vRealize-Operations-Manager/6.7/vrealize-operations-manager-67-reference-guide.pdf to see which definition metrics, properties and alerts are available for vROps 6.7.