Then you have 24 TB with RAID10, not 30 TB. I guess that's why he was wondering.
Technically I've got 18tb raid 10 and 12TB raid 1, I just didn't think it mattered and I was too lazy to explain that on my phone ( • ‿ • )
The 6x6TB were previouly in a Synology NAS (roughly 8yrs old now) and I was planning to slowly migrate everything over to 12TB disk's as things start failing