RAID 6 maximises capacity and survives any two failures; RAID 10 maximises write performance and rebuilds fastest. The right choice depends on your workload — compare them on your drives in the RAID calculator (6 vs 10).
Capacity and resilience
RAID 6 gives (n−2) × drive size usable and tolerates any two simultaneous failures across the array. RAID 10 gives n/2 × size — only 50% efficiency — and guarantees surviving one failure, with up to one per mirror pair if losses do not collide.
For pure capacity per pound, RAID 6 wins comfortably. Eight 16 TB drives give 96 TB in RAID 6 versus 64 TB in RAID 10. See the RAID 6 and RAID 10 calculators.
Write performance — RAID 10's advantage
RAID 6 carries a ×6 write penalty: each host write costs six back-end I/Os to update data and two parities. RAID 10 has only a ×2 penalty (write to both mirror halves). For write-heavy transactional databases, that difference is large and consistent.
RAID 10 also rebuilds far faster: it copies from the surviving mirror rather than recalculating parity across the whole array, so performance during a rebuild stays high and the risk window is short.
When to choose which
Choose RAID 6 for bulk file, backup-target, media and read-heavy capacity workloads where you want the most usable space and two-drive resilience. Choose RAID 10 for SQL/Oracle databases, busy virtualisation and any latency-sensitive, write-heavy workload.
Many estates run both: RAID 10 on flash for databases and VMs, RAID 6 on nearline HDD for capacity and backups. Our storage solution finder helps match the platform.