Default RAID policies for aggregates
Either RAID-DP or RAID-TEC is the default RAID policy for all new aggregates. The RAID policy determines the parity protection you have in the event of a disk failure.
RAID-DP provides double-parity protection in the event of a single or double disk failure. RAID-DP is the default RAID policy for the following aggregate types:
All flash aggregates
Flash Pool aggregates
Performance hard disk drive (HDD) aggregates
A new RAID policy called RAID-TEC is available. RAID-TEC is supported on all disk types and all platforms, including AFF. Aggregates that contain larger disks have a higher possibility of concurrent disk failures. RAID-TEC helps to mitigate this risk by providing triple-parity protection so that your data can survive up to three simultaneous disk failures. RAID-TEC is the default RAID policy for capacity HDD aggregates with disks that are 6 TB or larger.