Browser-based storage planning

RAID Calculator

Visualize usable storage, redundancy, and wasted capacity before building your RAID array.

Private by designCalculations stay in your browser

Step one

Configure drives and RAID

0 / 24 bays

Choose a capacity to install a drive. Add the same size more than once or mix sizes to model an existing inventory.

Example configurations

4-bay storage enclosureOriginal CSS hardware visualization

Array planner online

⌁NX STORAGE

Selected drives: 0
Total raw capacity: 0 TB
Drive mix: No drives installed

Advanced optionsEstimate filesystem and reserved system capacity

Account for filesystem overheadOptional configurable estimate; not vendor-specific. Reserved system space per driveGBDefaults to zero and is deducted from each physical drive.

RAID configuration

Select RAID to calculate

Choose one or more valid RAID types. Nothing is selected by default.

Install drives to begin

Capacity, protection, and unused space will appear here as you build the enclosure.

RAID is not a backup.Keep independent, tested copies of important data.

Storage architecture reference

RAID at a glance

Capacity outcomes are estimates. Controller behavior, pairing, metadata, and vendor implementations can differ.

RAID	Minimum drives	Usable capacity model	Fault tolerance	Typical use
Basic	1	Sum of independent disks	None	Simple individual volumes
JBOD	1	Sum of all disks	None	Maximum pooled capacity
RAID 0	2	N × smallest disk	None	Speed where data loss is acceptable
RAID 1	2	Smallest disk	Mirror dependent	Straightforward mirroring
RAID 5	3	(N − 1) × smallest disk	1 drive	Capacity with single parity
RAID 6	4	(N − 2) × smallest disk	2 drives	Dual-parity resilience
RAID 10	4, even	Sum of mirror-pair minima	Pairing dependent	Performance and mirrors
SHR	1	Capacity-layer estimate	1 drive when redundant	Flexible mixed-size arrays
SHR-2	4	Dual-protected layers	2 drives	Flexible dual protection

Technical notes

Frequently asked questions

What is RAID?

RAID combines physical drives to target capacity, performance, availability, or a balance of those goals.

Does RAID replace backup?

No. RAID can improve availability during certain drive failures, but it does not protect against deletion, corruption, malware, theft, or a failed enclosure.

Why is some capacity unused?

Traditional RAID generally treats every member as if it were the size of the smallest drive. Larger members can therefore have capacity that does not participate.

Can I mix different drive sizes?

Often, yes, but capacity efficiency and supported layouts depend on the RAID implementation and storage controller.

What is RAID 5?

RAID 5 stripes data and distributed parity across at least three drives and can tolerate one member failure.

What is RAID 6?

RAID 6 uses dual distributed parity across at least four drives and can tolerate two member failures.

What is RAID 10?

RAID 10 stripes across mirrored pairs. It requires an even drive count; results can depend on drive pairing and controller behavior.

What are SHR and SHR-2?

They are represented here as educational capacity-layer estimates with one- or two-drive protection. Actual support and behavior differ by NAS vendor.

Why is TB different from TiB?

Drive makers use decimal terabytes: 1 TB is 10¹² bytes. A tebibyte is binary: 1 TiB is 2⁴⁰ bytes, so the same byte count has a smaller TiB number.