TLDR ; Seagate's new line of Ironwolf Pro drives has higher annual utilization, higher MTBF and supports an unlimited number of drive bays.
It was the Ironwolf Pro series that started with the free data recovery service (which was later extended to Ironwolf as well). This quarter, Seagate introduced new part numbers ending in NT001 instead of NE000. The spec sheet shows 3 major improvements - 2 in the reliability matrix and one with the support of number of bays.
The new series supports an unlimited number of bays, while the old series had upto 24 bay support The MTBF of the new drives is 2.5 million hours (previously 1.2 million hours) and the annual workload of the new drives is 550 TB per year (previously 300 TB per year). Seagate has not published the AFR (Annualized failure rates) for the new and old hard drives but mostly the new drive would have lower AFR than the old ones.
Here is a list of all the new part numbers
|Old Part Number||New Part Number|