Use this calculator to determine usable storage capacity, fault tolerance, and estimated performance for various RAID configurations. Supports standard RAID levels (0, 1, 5, 6, 10), nested arrays (RAID-50, RAID-60), and ZFS RAID-Z variants (Z1, Z2, Z3). Each configuration includes detailed explanations, minimum requirements, and recommended use cases.
Enter your disk configuration and click Calculate to see results.
RAID (Redundant Array of Independent Disks) is a data storage technology that combines multiple physical disk drives into a single logical unit. Depending on the RAID level chosen, this can provide improved performance, data redundancy (fault tolerance), or both.
RAID is commonly used in servers, workstations, and network-attached storage (NAS) devices where data reliability and/or performance is critical. It's important to understand that RAID is not a backup—it protects against hardware failure but not against data corruption, accidental deletion, or disasters.
The best RAID level depends on your specific requirements:
- Maximum performance, no redundancy: RAID-0
- Simple redundancy, 2 disks: RAID-1
- Balanced capacity and protection: RAID-5 or RAID-Z1
- Enhanced protection for large arrays: RAID-6, RAID-Z2, or RAID-Z3
- High performance with redundancy: RAID-10
- Enterprise-scale arrays: RAID-50 or RAID-60
Hardware RAID uses a dedicated controller card with its own processor and memory. Benefits include better performance, battery-backed cache for write protection, and OS independence. However, hardware RAID controllers can be expensive and may require proprietary replacement if they fail.
Software RAID (Linux mdadm, Windows Storage Spaces, ZFS) uses the system CPU for RAID calculations. Modern CPUs handle this efficiently, and software RAID offers flexibility, lower cost, and easier migration between systems. ZFS provides additional features like checksumming and self-healing.
The performance multipliers shown are theoretical estimates. Real-world performance depends on many factors:
- Workload type: Sequential vs. random I/O patterns
- Block size: Large blocks favor sequential; small blocks favor random
- Controller quality: Cache, processor speed, and firmware
- Disk type: SSDs have different characteristics than HDDs
- Read/write ratio: Parity RAID levels suffer more on writes
Always benchmark your specific configuration for accurate performance data.
RAID is not a substitute for backups. RAID can protect against single points of hardware failure, but it cannot protect against:
- Accidental file deletion
- Ransomware and malware
- Filesystem corruption
- Controller failure (hardware RAID)
- Multiple simultaneous disk failures
- Fire, theft, or natural disasters
Always maintain regular backups following the 3-2-1 rule: three copies of your data, on two different types of media, with one copy stored offsite.