To improve performance, may want to separate the volume storing database files and WAL files. Similarly, one may want to use a dedicated volume for a new tablespace. The operator gives the end user the flexibility to create a FEPCluster with multiple PVs and select a suitable storage class for the PV. For example, one can create a FEPCluster with data volume, wal volume on a storage class backed up by SSD and a log volume on a storage class backed up by HDD.