Enable read reallocation on a volume?

Hi,

We're having some read latency issues on a particular volume in our environment. We can see both random- and sequential reads on the particular volume. Block size also seems to be bigger than on our other NFS datastores in our environment. 

I have enabled read reallocation with the space-optimized option on the volume. Question: Do I also need to run a manually reallocation on the volume or will the volume start the reallocation in the background? Reallocate show doesn't show anything, only "This table is currently empty".

Environment: 

Ontap 8.3.1

VMware vSphere 6

NFS datastore, VMDK

BR,

David T