About HomeServerCalc

Why this site exists

Search for a RAID calculator and every result belongs to somebody who sells storage. Synology's tool models SHR. ZFS-flavoured tools model RAIDZ. Controller vendors model the classic levels. Each is accurate about its own scheme and silent about the others, which means the one comparison a buyer actually needs, the same drives evaluated under every layout at once, does not exist on any manufacturer site.

That gap matters most exactly where the money is. On mixed drive sizes SHR pulls ahead, because it slices the drives into horizontal bands and protects each band separately, while standard RAID and every ZFS vdev truncate each member down to the smallest drive and strand the difference. A vendor tool will not show you the size of what you are stranding. Ours does.

The one framing that runs through everything here

The drives are the purchase. An eight-bay enclosure is roughly $1,300 and the eight drives that fill it are $2,000 to $4,000, so the chassis is a quarter to a third of the spend. Drives also fail and get upgraded on a rolling schedule, which the enclosure does not. Most buying guides in this category have that priority backwards, and the result is people spending three weeks choosing between two boxes that differ by $80 and then buying whatever drives were cheapest.

So the drive pages here are treated as the important ones: how to choose NAS drives, the drive comparison, and cost per terabyte.

How the numbers are produced

Capacity figures on this site are computed, not typed. The reference charts and the calculators share one arithmetic module, so a chart cannot drift out of agreement with the tool that generated it, and every figure can be checked with the formula printed alongside it.

Units are consistent everywhere. Capacity is decimal terabytes, the number printed on the drive label, with binary tebibytes shown alongside where it matters. One TB is 1,000,000,000,000 bytes and one TiB is 1,099,511,627,776, a fixed ratio of 0.909495, which is why every capacity reads 9.05 percent smaller once your operating system reports it. Nothing is missing. It is the same bytes counted in a different base, and it is explained in full on the TB against TiB chart.

Specification tables come from published manufacturer data. Where a vendor does not publish a figure, or where sources disagree, the cell is omitted rather than estimated. A wrong specification on a specification page is the fastest way to lose a reader who came here precisely because they intend to check the numbers.

What we do not do

We do not test hardware in person, and we will never pretend otherwise. Any site claiming hands-on testing of forty drives is telling you a story. What we do is compare published manufacturer specifications and datasheets, cross-check them against published large-fleet reliability statistics and verified owner reviews, and flag where a spec sheet is quietly measuring something different from a competitor's.

We also do not publish per-model drive failure rates, because honest per-model figures move every year and any single number is a snapshot rather than a property of the model. What the reliability chart gives you instead is the arithmetic: annualised failure rate against drive count and years, which is the number that actually decides how much parity you need.

How the site makes money

HomeServerCalc is a participant in the Amazon Services LLC Associates Program. When you buy through a link here we earn a commission, at no extra cost to you. That is the entire business model, and it never decides which product is recommended. Full terms are on the affiliate disclosure page.

Two consequences worth stating plainly. First, we recommend the cheaper option often, because on this site the honest answer is usually that the money would do more for you in drives than in a faster enclosure. Second, where a product is genuinely not sold on Amazon, we link to a search rather than invent a listing, and where an ASIN cannot be verified we leave it out.

What this site is not

Everything here is researched guidance, not professional data recovery, electrical or IT advice. RAID protects against a drive failing. It does nothing about accidental deletion, ransomware, a controller writing garbage to every member, theft, fire or flood, because each of those reaches every drive in the chassis at the same instant. Keep verified backups regardless of what any calculator on this site tells you, and have mains wiring done by a licensed electrician.

Contact

Corrections are welcome and taken seriously, particularly on the arithmetic. If a figure here is wrong, say so on the contact page and it gets fixed.