Synology Raid Calculator

Estimate available storage capacity, data redundancy, and protection efficiency for your Synology NAS.

Parameter	Value	Description
Total Raw Storage	8.00 TB	Sum of all physical drive capacities.
RAID Configuration	SHR	Type of array data organization.
Disk Fault Tolerance	1 Disk	Number of drive failures tolerated.
Efficiency	50%	Available space vs Raw space.

What is a Synology RAID Calculator?

A synology raid calculator is an essential planning tool for Network Attached Storage (NAS) users. It allows you to simulate how different hard drive capacities and RAID levels interact within the Synology DSM operating system. By using a synology raid calculator, you can determine how much usable space remains after accounting for data redundancy and system overhead.

Whether you are setting up a 2-bay DiskStation for home photos or an 8-bay rackmount unit for business virtualization, the synology raid calculator helps avoid the common mistake of buying mismatched drives that result in wasted storage. This tool specifically focuses on Synology Hybrid RAID (SHR), a proprietary technology that offers more flexibility than traditional RAID levels.

Synology RAID Calculator Formula and Mathematical Explanation

The math behind a synology raid calculator depends heavily on the RAID level selected. Unlike simple arithmetic, RAID involves logic gates and parity calculations.

• RAID 0: Available = Sum of all disks. (No Redundancy)
• RAID 1: Available = Size of the smallest disk. (1-disk Mirror)
• RAID 5: Available = (Number of disks – 1) × Size of smallest disk.
• SHR: Available = (Total Capacity) – (Size of the largest disk).

Variable	Meaning	Unit	Typical Range
N	Number of Hard Drives	Count	1 – 24
Dmax	Largest Drive Capacity	TB	1TB – 22TB
Stotal	Sum of all Drive Capacities	TB	2TB – 500TB
P	Parity Overhead	TB	Varies by RAID

Practical Examples

Example 1: Mixed Drive Sizes in SHR
If you use a synology raid calculator for a setup with two 4TB drives and two 8TB drives using SHR, the calculation is: (4+4+8+8) – 8 = 16TB usable space. The synology raid calculator demonstrates that SHR effectively utilizes the extra space that RAID 5 would have wasted.

Example 2: RAID 6 for High Security
Using four 10TB drives in RAID 6. The synology raid calculator shows: (4 – 2) × 10 = 20TB usable. 20TB is reserved for double parity, allowing two simultaneous drive failures.

How to Use This Synology RAID Calculator

1. Select RAID Level: Choose between SHR, SHR-2, or standard RAID levels (0, 1, 5, 6, 10).
2. Input Drive Sizes: Enter the capacity of each drive currently in your NAS or planned for purchase.
3. Review Results: The synology raid calculator instantly updates the “Available Capacity” and “Protection Space” metrics.
4. Analyze the Chart: Use the visual bar to see the ratio of usable space to redundancy overhead.

Key Factors That Affect Synology RAID Calculator Results

1. Decimal vs. Binary Conversion: Drive manufacturers define 1TB as 1,000,000,000,000 bytes, while Synology DSM uses binary (TiB). A synology raid calculator result should be multiplied by ~0.909 to see what the OS will actually report.

2. BTRFS Metadata: Using the BTRFS file system takes about 4% of the volume capacity for metadata and snapshots, a detail often missed without a synology raid calculator.

3. Drive Failure Tolerance: RAID 5 and SHR offer 1-disk protection, while RAID 6 and SHR-2 offer 2-disk protection. Higher protection means less usable space.

4. Hot Spares: If you designate a drive as a “Hot Spare,” the synology raid calculator raw capacity decreases because that drive remains idle until a failure occurs.

5. Expansion Limits: Older Synology models have a 16TB or 32TB volume limit. Even if the synology raid calculator shows more space, the hardware might limit you.

6. Mismatched Drives: In traditional RAID 5, if you mix a 4TB and 8TB drive, the 8TB drive is treated as a 4TB drive. The synology raid calculator highlights how SHR solves this.

Frequently Asked Questions (FAQ)

Can I change RAID levels later?

Yes, Synology allows migrating from RAID 1 to RAID 5 or SHR to SHR-2, but you cannot “downgrade” (e.g., RAID 5 to RAID 1) without deleting the volume.

What is SHR?

Synology Hybrid RAID (SHR) is an automated RAID management system that makes it easier to mix drives of different sizes, as shown in our synology raid calculator.

Is RAID 0 safe for my data?

No. RAID 0 offers no redundancy. If one drive fails, all data is lost. Use the synology raid calculator to see how RAID 1 or SHR adds safety.

Why is my usable space lower than the calculator?

The synology raid calculator gives the mathematical RAID capacity. Your actual usable space is lower due to file system formatting and the 1000 vs 1024 byte conversion.

How many drives can I have in SHR?

SHR supports as many drives as your Synology NAS has slots, from 1 to 24+ with expansion units.

Does RAID replace a backup?

No. RAID protects against hardware failure, not accidental deletion, ransomware, or fire. Always have an offsite backup.

Which is better, RAID 5 or SHR?

For most users, SHR is better because it allows for easier future upgrades with larger drives.

Can I use SSDs and HDDs in the same RAID?

It is not recommended. The array’s speed will be limited by the slowest drive, and wear levels will vary significantly.

Related Tools and Internal Resources

• Hard Drive Reliability Guide – Understand failure rates for NAS drives.
• NAS Setup Checklist – A step-by-step guide to configuring your new Synology.
• Best Drives for Synology – Comparison of IronWolf vs WD Red vs Exos.
• Cloud Backup Strategies – How to back up your RAID array to the cloud.
• BTRFS vs EXT4 Explained – Choosing the right file system for your storage pool.
• Data Recovery Services – What to do if your RAID array fails completely.