The PureDisk 6.6.1 compatibility list (http://www.symantec.com/business/support/index?page=content&id=TECH139108) has a chart showing the compatibility of PureDisk versions against NetBackup version. In the document at that technote, look at the table starting on page 23.
You'll find there that PureDisk 6.6.1 is supported on most NetBackup media server platforms since NetBackup 6.5
Yes, NetBackup 7.5.0.5 supports the PureDisk Deduplication Option using a PureDisk 6.6.1 storage pool.
