I just setup a new NAS and wanted to create a RAID 5 with 4*14TB harddisks.
You should really think about if a RAID5 array created with 14 TB disks is still an appropriate way nowadays. If you had to replace a disk in the future the resilvering process takes forever and entails the risk that a second disk fails. Which then means a complete loss of the array.
So I deactivated two harddisks and created just a stripe RAID (RAID 0).
You are aware, that RAID0 has no data redundancy? If one disk fails you lost the array. A RAID 0 is normally not useful in a NAS, especially with a GB Lan connection.
How do you want to organize your data backup system?