What type of restore performance are you getting from the HPE StoreOnce?
What HPE StoreOnce Appliance are you using? Is this over IP or over FC?
There are specific counters reported in CVD to indicate which potential API/operation (read, write, flush, close and etc) could be the bottleneck.
If further review of performance is required, I would recommend to engage Commvault support, so they can review the counters