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Raid & ZFS calculator
RAID & TCO calculator
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Everything you need to know about RAID & ZFS calculations
Choosing the right storage configuration is crucial for the security of your data. Whether you’re setting up a NAS with TrueNAS, Unraid, or a Proxmox server, our calculator helps you anticipate the actual available capacity after formatting and system space reservation (SLOP).
Why use a ZFS calculator?
Unlike traditional hardware RAID, the ZFS file system manages data in storage “pools.” Understanding the difference between:
RAIDZ1 : Tolerates the failure of a single disk (RAID 5 equivalent). Ideal for home storage.
RAIDZ2 : Double parity for increased security (RAID 6 equivalent). Recommended for high-capacity disks.
Mise en miroir (Mirroring) : Offers the best read/write performance, but with a 50% loss of space (equivalent to RAID 10).
Performance and IOPS
Our tool does more than just calculate GB. It also estimates the write penalty and IOPS of your disk array, thus preventing unpleasant surprises when deploying your virtual machines or backups.
Why Use a ZFS RAID Calculator for Your Storage Server?
Paragraph: ZFS (Zettabyte File System) has become the gold standard for data integrity on platforms like TrueNAS, Proxmox, and Ubuntu. However, calculating usable capacity after parity overhead (RAID-Z1, RAID-Z2, RAID-Z3) or mirroring can be tricky. Our online tool helps you simulate Vdev configurations and predict available storage space while accounting for “slop space,” swap partitions, and system reserves.
Optimize Your Server Performance with Our Free Tools
Paragraph: Beyond raw capacity, disk performance for HDDs and SSDs is critical for a stable build. We have developed a suite of specialized tools for sysadmins and hardware enthusiasts:
FIO Results Visualizer: Convert complex JSON logs into readable charts to compare IOPS, throughput, and latency.
RAID Rebuild Time Estimator: Calculate how long it will take to resilver your ZFS pool after a drive failure to assess your data loss risk.
PC Bottleneck Calculator: Identify if your CPU or GPU is limiting your hardware performance in gaming or professional workloads.
How much usable space do I get with RAIDZ2?
RAIDZ2 requires at least 4 disks and uses 2 of them for parity. Your usable space is calculated as (N-2) times the smallest disk capacity. Our calculator also subtracts the ZFS overhead for more accuracy.
Is RAIDZ1 safe for large hard drives?
For modern high-capacity drives (8TB+), RAIDZ2 is highly recommended. The “resilver” (rebuild) time for large drives is long, and a second failure during this process would result in total data loss in RAIDZ1.
What is the ZFS SLOP space reservation?
ZFS reserves about 3.2% (1/32) of the pool capacity as “SLOP” space. This prevents the file system from becoming completely locked or extremely slow when it reaches near-full capacity.
Does this calculator work for TrueNAS and Unraid?
Yes! While Unraid uses a different parity system for its main array, it supports ZFS pools. TrueNAS is built entirely on ZFS. Our tool provides accurate estimations for both systems.
What are IOPS in a RAID configuration?
IOPS (Input/Output Operations Per Second) represent the speed of your array. In a RAIDZ configuration, the write IOPS are generally limited to the speed of a single drive in the VDEV, while read IOPS scale with the number of data drives.
RAID & ZFS Calculator
This RAID performance calculator and total cost of ownership (TCO) analysis tool is designed to optimize your storage infrastructure. Get accurate estimates and recommendations based on real-world business scenarios.
Why use our raid zfs calculator ?
Professionel precision
Our algorithms incorporate real-world write penalties, controller overhead, and system limitations to provide results close to real-world performance.
Conservative approach
Unlike optimistic calculators, we apply reduction factors based on company experience to avoid unpleasant surprises.
Economic analysis
Calculate the total cost of ownership (TCO) over 5 years, including purchase, electricity, maintenance and replacement of components.
Supported data
A complete calculator for all your storage needs
Advanced Features
Flexible configuration
Adjust the number of disks per RAID group, multiple groups, and read/write ratios according to your needs.
RAID & ZFS support
All standard RAID levels (0, 1, 5, 6, 10) plus ZFS variants (RAIDZ1, RAIDZ2, RAIDZ3) with their specific features.
Smart validation
The calculator automatically checks the validity of the configurations and warns you of any impossible configurations.
Responsive interface
Usable on computers, tablets, and mobile devices with an intuitive interface and clear visualizations.
Real-time calculations
Instant results during editing with separate display of read and write performance.
Business scenarios
Pre-configured settings for different use cases: office automation, virtualization, databases, archiving.
⚠️ Important to remember
This calculator provides estimatesBased on typical configurations and conservative factors. Actual performance may vary depending on :
- The model and specifications of the hard drives
- The RAID controller used (hardware vs. software)
- System configuration (CPU, RAM, data bus)
- The type of workload and access patterns
- Firmware and file system configuration
Recommandation : Use these results as a basis for planning, then conduct tests with your specific equipment to validate actual performance.
Typical use cases
IT integrator
Quickly size your clients' storage infrastructure. Present detailed total cost of ownership analyses and justify your technical choices.
Storage consulting
Use this tools to evaluate the performance and costs of different RAID configurations during audits or migration projects.