RAID 6 vs RAID 10
RAID 6 gives you more usable capacity and survives any two drive failures. RAID 10 is faster, especially on writes, and rebuilds quickly, but costs half your capacity and only guarantees one failure. For large, read-heavy bulk storage, RAID 6. For write-heavy or latency-sensitive workloads like VMs and databases, RAID 10.
Updated 2026-06-03 · by Jonathan Caruso
Side by side
| RAID 6 | RAID 10 | |
|---|---|---|
| How it works | Striping with two parity drives | Striped pairs of mirrors |
| Minimum drives | 4 | 4 (even count) |
| Usable capacity | n - 2 drives | n / 2 drives (50%) |
| Drives that can fail | Any 2 | At least 1 (up to one per mirror) |
| Read performance | Good | Very good |
| Write performance | Slower (double parity) | Fast |
| Rebuild | Slow, stresses every disk | Fast, copies one mirror |
| Best at | Capacity with two-disk safety | Speed and fast rebuilds |
How each one works
RAID 6 stripes data across the array and keeps two drives' worth of parity, spread across all the disks. You lose the capacity of two drives, and in exchange the array survives any two failures at once. That second parity drive is what makes it safe on large modern disks.
RAID 10 is a stripe of mirrors. Each drive has a full copy in its mirror, and those mirrors are striped for speed. You lose half your raw capacity, but writes are fast (no parity to calculate) and recovery is simple: replacing a failed drive just copies its mirror.
Capacity and safety vs speed
RAID 6 wins on usable capacity and guaranteed fault tolerance. With six 8 TB drives you get about 32 TB usable and can lose any two drives. RAID 10 on the same six drives gives 24 TB and only guarantees surviving one failure, though it often survives more if the failures land in different mirrors.
RAID 10 wins on write performance and rebuild safety. There is no parity math on every write, so databases, busy VMs, and small-file workloads are noticeably faster. And when a drive fails, RAID 10 rebuilds by copying a single healthy mirror, which is quick and low-stress. RAID 6 rebuilds by reading the entire array to recompute parity, which is slow and works every remaining disk hard.
The rebuild and the real risk
On large drives, rebuild behavior matters as much as the failure count. RAID 6 can survive a second failure during a rebuild, which is its whole point, but those rebuilds are long and stressful on the remaining disks. RAID 10 rebuilds fast, but a second failure in the same mirror during that window loses data.
In practice both are safe choices on big drives, unlike RAID 5. RAID 6 buys you certainty (any two can fail), while RAID 10 buys you speed and a gentle, fast rebuild. Pick the property your workload values more.
What to run
For a large, mostly-read bulk array (media, backups, archives), RAID 6 is usually the better deal. You get more usable space and the comfort of surviving any two failures, and the slower writes rarely matter for that kind of data. On ZFS this is RAIDZ2.
For write-heavy or latency-sensitive storage (VM datastores, databases, anything with lots of small writes), RAID 10 is the better engine. On ZFS the equivalent is a stripe of mirrors. Run your real disk count through the RAID and ZFS storage calculator to see usable capacity and fault tolerance, and if you are weighing single versus double parity, see RAID 5 vs RAID 10.
Where RAID 6 wins
- Best usable capacity of the two, only two drives spent on parity.
- Survives any two simultaneous drive failures.
- Great for large, read-heavy bulk storage.
Where RAID 10 wins
- Fast reads and especially fast writes, with no parity penalty.
- Quick, low-stress rebuilds that copy a single mirror.
- Ideal for write-heavy and latency-sensitive workloads.
Which to pick, by situation
| Your situation | Pick | Why |
|---|---|---|
| Large bulk media or backup array | RAID 6 | More usable capacity and survives any two failures. |
| VM storage or databases (write-heavy) | RAID 10 | No parity penalty on writes, fast low-stress rebuilds. |
| Four drives, maximum fault tolerance | RAID 6 | Survives any two of the four failing. |
| Four drives, maximum speed | RAID 10 | Two mirrors striped for fast reads and writes. |
The verdict
Run RAID 6 for large, read-heavy bulk storage where capacity and surviving any two failures matter most. Run RAID 10 for write-heavy or latency-sensitive workloads like VMs and databases, where fast writes and quick rebuilds win. Both are safe on large drives, unlike RAID 5. Check your real numbers in the RAID and ZFS storage calculator before deciding.
Choose RAID 6 if you want maximum usable capacity and the certainty of surviving any two drive failures, and you can accept slower writes and rebuilds.
Choose RAID 10 if you want fast writes and quick, low-stress rebuilds for a latency-sensitive workload, and you can spend half your capacity on mirroring.
FAQ
Is RAID 6 or 10 better for 4 drives?
With four drives, RAID 6 survives any two failing and gives you the capacity of two drives. RAID 10 survives at least one (sometimes two if they are in different mirrors) and is faster. Choose RAID 6 for maximum safety and capacity, RAID 10 for speed.
Is RAID 10 suitable for home use?
Yes. RAID 10 is a great home choice for write-heavy or latency-sensitive storage like VMs and databases, where its speed and quick rebuilds shine. For bulk media where capacity matters more, RAID 6 is often the better value.
What is the primary disadvantage of RAID 10?
You lose half your raw capacity, since every drive is mirrored, and it only guarantees surviving a single drive failure (a second failure in the same mirror loses data). It also needs an even number of drives, at least four.
What are the disadvantages of RAID 6?
Writes are slower because of double-parity calculation, and rebuilds are slow and stress every remaining disk. You also give up two drives of capacity to parity. In return you survive any two failures, which is its main appeal on large drives.