RAID 0 and RAID 1 are opposites: RAID 0 is all speed and capacity with zero safety, RAID 1 is a safe mirror at half the capacity. Size both in the RAID calculator (0 vs 1).
RAID 0 — striping for speed
RAID 0 splits data across all drives with no redundancy, giving 100% usable capacity and the best read/write throughput of any level. The catch is fatal: any single drive failure loses the entire array, and the risk grows with each drive you add. There is no rebuild.
RAID 0 is only for disposable, reproducible or separately-protected data — scratch space, render caches, read caches. Never for a single source of truth.
RAID 1 — mirroring for safety
RAID 1 writes an identical copy to each drive. A two-drive mirror gives one drive of usable capacity (50% efficiency) and survives a failure; reads can be served from either copy, and rebuilds are a simple, fast copy. It's the standard for boot/OS drives and small critical datasets.
The cost is capacity: you buy two drives to use one. But for data you can't lose on a small volume, that simplicity and safety is worth it. See the RAID 1 calculator.
Choosing — and beyond two drives
Pick RAID 0 only for throwaway speed; pick RAID 1 for safety on a small volume. They sit at opposite ends, which is why most real arrays use a level that blends both — RAID 10 (striped mirrors) for speed and safety together, or parity RAID for capacity-efficient redundancy.
If you have four or more drives and want RAID 1's safety plus more capacity and speed, jump to RAID 10 rather than scaling RAID 1.