RPA Repository on Vault Drives

I recommend you download the CLARiiON Best Practices for Fibre Channel Storage, in particular the section titled Vault and PSM Effects. This will give you an idea of the potential performance impacts to the array and hosts when placing LUNs on these drives.

That being said I don't know that level of performance required for the repository volume. It stores the configuration information and markers for the consistency groups, but it is the journal volumes that are storing the actual replicated data. So it might not be an issue for you if you place the repository on the vault drives.

Is your array heavily loaded with disks and hosts already? What is the average CPU utilization of the SPs of the array?