RAID 0 Capacity Calculator – Stripe Size, Speed and Risk

Redundancy isn’t built-in. RAID 0 doesn’t do any mirror copies or parity calculations. It’s a pure speed/capacity play. Gamers who has massive game collections, video editors working on 4K renders, they’re into it. Plug in four drives to get four times the space and approximately four times the speed.

But there’s no safety net. Data is split up evenly among all the drive, so if one drive fails everything is lost. There’s a calculator that can help explain the risk/reward calculation.

How to Plan Your RAID 0 Storage

Calculating capacity is as easy as 2 + 2 = 4. The formula here is total capacity = (number of drives) x (size of smallest drive). Why does it matter? If you use two drives, one 500 GB and another 1 TB; they’ll max out at 1 TB, since that’s how much the smaller drive can hold. The bigger drive will be wasted, taking up half its capacity to keep pace with the other. That’s why the calculator figures this in for you; otherwise, you might think you’re getting more than just the biggest piece based off its raw specs.

At 100% usable efficiency, RAID 0 doesn’t reserve any bytes for protection. Each byte is fair game for inclusion in your storage pool, and that’s why people like it, even though it’s volatile.

Binary vs. Decimal Units: This one trips people up, too. Drives are sold in units of terabytes (powers of ten) by manufacturers but reported in tebibytes (powers of two) by operating systems. Your 8 TB array will show up as about 7.28 TiB on your desktop. It’s not that something is wrong… It’s just a difference in how computers are built and how drives is marketed. You’ll see both numbers displayed here so you’re never confused as to what you get when the drive spins up.

In RAID 0, speed increase steadily with the number of drives used. For example, one drive gives 1x speed, while two drives give 2x speed. Striped data vs. A parity array (which must calculate overhead during a write operation) improves both reads and writes. That’s why you see higher numbers on both sides. Controller overhead + bus limitations never let you reach those theoretical maxes in real world performance. The efficiency slider in the calc lets you scale down performance to match reality different than the marketing brochure.

And finally there’s the risk. It is the most important output. This has no room for error. One bad drive and you’re down. Every additional drive increases the odds of failure. At 2 percent per year for every single drive, a four-drive array has a nearly 8 percent chance it will fail completely each year. Faster? Yes. It is exponentially more exposed. Also yes.

Data are then chunked into stripes according to stripe size. For a sequential workload like video files, larger stripes are better as they allow each disk to stream efficienty. Random access pattern workloads like databases may find smaller stripes beneficial. You get the best performance here without changing any hardware.

Use RAID 0 for data that is already backed up elsewhere or is temporary anyway. Use it for game libraries to download again if necessary, scratch disks, or render caches. Anything that isn’t the only copy of something you can’t recieve back in another way. Build with a backup plan that accounts for this risk; the calculator will help you build an array sized both for space and for speed. Don’t build it until you have another copy somewhere. In RAID 0, there should of been no rebuild, just restore.