Synology Storage Calculator

Plan your NAS capacity, understand RAID types, and estimate usable storage.

Synology Storage Calculator

RAID Type Comparison

A quick overview of common RAID types and their characteristics for Synology NAS.

RAID Type	Minimum Drives	Fault Tolerance	Usable Capacity (Same Size Drives)	Best Use Case
RAID 0	2	0 drives	N * Drive Size	Maximum speed, no data protection.
RAID 1	2	N-1 drives	1 * Drive Size	High redundancy for small systems, mirroring.
RAID 5	3	1 drive	(N-1) * Drive Size	Good balance of capacity, performance, and redundancy.
RAID 6	4	2 drives	(N-2) * Drive Size	Higher redundancy, tolerates two drive failures.
RAID 10	4 (even)	N/2 drives	(N/2) * Drive Size	High performance and redundancy, but lower capacity.
SHR-1	1 (2 for redundancy)	1 drive	(N-1) * Drive Size (for same size drives)	Flexible, optimized for mixed drive sizes, 1-disk redundancy.
SHR-2	2 (3 for redundancy)	2 drives	(N-2) * Drive Size (for same size drives)	Flexible, optimized for mixed drive sizes, 2-disk redundancy.

What is a Synology Storage Calculator?

A Synology Storage Calculator is an essential online tool designed to help users plan and estimate the usable storage capacity of their Synology Network Attached Storage (NAS) devices. It takes into account critical factors such as the number of hard drives, their individual capacities, and the chosen RAID (Redundant Array of Independent Disks) configuration to provide an accurate projection of available space. This calculator is invaluable for anyone looking to purchase a new Synology NAS, expand an existing one, or simply understand the implications of different storage setups.

Who Should Use a Synology Storage Calculator?

• Prospective Synology NAS Owners: To determine the optimal drive configuration and RAID type before making a purchase.
• Current Synology Users: For planning storage expansion, upgrading drives, or reconfiguring RAID arrays.
• IT Professionals and Small Businesses: To accurately budget for storage needs and ensure data redundancy.
• Data Hoarders and Media Enthusiasts: To ensure sufficient space for growing photo, video, and document collections.

Common Misconceptions about Synology Storage

Many users mistakenly believe that simply adding up the capacities of all their drives will give them their total usable storage. This is a significant misconception. RAID configurations, especially those designed for data redundancy (like RAID 1, 5, 6, 10, SHR-1, SHR-2), reserve a portion of the total raw capacity for parity information or mirroring, which reduces the actual usable space. Another common error is underestimating future storage needs, leading to premature expansion or data migration challenges. The Synology Storage Calculator helps clarify these complexities by providing precise figures.

Synology Storage Calculator Formula and Mathematical Explanation

The core of the Synology Storage Calculator lies in its ability to apply specific RAID formulas to your input parameters. While Synology Hybrid RAID (SHR) offers flexibility with mixed drive sizes, for simplicity and common scenarios, we often assume drives of the same size. The formulas below illustrate how usable storage is derived for various RAID types:

Step-by-Step Derivation:

1. Determine Raw Storage: This is the simplest calculation:
   Raw Storage (TB) = Number of Drives (N) × Drive Size (D)
2. Apply RAID Overhead: Each RAID type has a different overhead for redundancy:
   • RAID 0 (Striping): No redundancy. Usable Storage = Raw Storage.
   • RAID 1 (Mirroring): One drive’s capacity is used for mirroring. Usable Storage = 1 × Drive Size (D).
   • RAID 5 / SHR-1 (Single Parity): One drive’s capacity is used for parity. Usable Storage = (N – 1) × D.
   • RAID 6 / SHR-2 (Dual Parity): Two drives’ capacity is used for parity. Usable Storage = (N – 2) × D.
   • RAID 10 (Striping + Mirroring): Half of the drives are used for mirroring. Usable Storage = (N / 2) × D.
3. Calculate Redundancy Overhead: This is the difference between raw and usable storage:
   Redundancy Overhead (TB) = Raw Storage (TB) - Usable Storage (TB)
4. Determine Fault Tolerance: This indicates how many drives can fail before data loss occurs.

Variables Table:

Variable	Meaning	Unit	Typical Range
N	Number of Drives	Units	1 – 24
D	Individual Drive Size	Terabytes (TB)	1 TB – 24 TB
RAID Type	Redundant Array of Independent Disks Configuration	N/A	RAID 0, 1, 5, 6, 10, SHR-1, SHR-2
Cost per Drive	Estimated cost of a single hard drive	USD ($)	$50 – $1000+

Practical Examples (Real-World Use Cases)

To better understand how the Synology Storage Calculator works, let’s look at a couple of practical scenarios:

Example 1: Small Office Setup with Data Protection

A small design studio needs a Synology NAS for collaborative file storage and client project backups. They prioritize data protection and want a good balance of capacity and redundancy.

• Inputs:
  • Number of Drives: 4
  • Drive Size (TB): 8 TB (each)
  • RAID Type: Synology Hybrid RAID (SHR-1)
  • Estimated Cost per Drive: $180
• Outputs (from Synology Storage Calculator):
  • Usable Storage: 24.00 TB
  • Raw Storage: 32.00 TB
  • Redundancy Overhead: 8.00 TB
  • Fault Tolerant Drives: 1
  • Total Estimated Cost: $720.00
• Interpretation: With 4x8TB drives in SHR-1, the studio gets 24TB of usable space, which is sufficient for their needs. They can lose one drive without data loss, providing crucial protection for their valuable project files. The total cost helps them budget effectively.

Example 2: Home Media Server with High Redundancy

A home user wants to build a robust media server to store a large collection of movies and TV shows. They are concerned about drive failures and want maximum protection, even if it means sacrificing some capacity.

• Inputs:
  • Number of Drives: 6
  • Drive Size (TB): 12 TB (each)
  • RAID Type: RAID 6
  • Estimated Cost per Drive: $250
• Outputs (from Synology Storage Calculator):
  • Usable Storage: 48.00 TB
  • Raw Storage: 72.00 TB
  • Redundancy Overhead: 24.00 TB
  • Fault Tolerant Drives: 2
  • Total Estimated Cost: $1500.00
• Interpretation: By choosing RAID 6, the user sacrifices 24TB of raw capacity for the ability to withstand two simultaneous drive failures. This provides a high level of data security for their irreplaceable media library, resulting in 48TB of usable storage. The Synology Storage Calculator clearly shows the trade-off between capacity and redundancy.

How to Use This Synology Storage Calculator

Our Synology Storage Calculator is designed for ease of use, providing quick and accurate results for your NAS planning. Follow these simple steps:

1. Enter Number of Drives: Input the total count of hard drives you plan to install in your Synology NAS. This can range from 1 to 24, depending on your NAS model.
2. Specify Drive Size (TB): Enter the capacity of each individual hard drive in Terabytes (TB). Ensure all drives are of the same size for the most straightforward RAID calculations.
3. Select RAID Type: Choose your desired RAID configuration from the dropdown menu. Options include Synology Hybrid RAID (SHR-1, SHR-2), RAID 0, RAID 1, RAID 5, RAID 6, and RAID 10. Each offers different levels of performance, capacity, and data protection.
4. (Optional) Enter Estimated Cost per Drive: If you want an estimate of the total hardware cost, input the approximate price of a single hard drive.
5. Click “Calculate Storage”: The calculator will instantly process your inputs and display the results.

How to Read Results:

• Usable Storage (TB): This is your primary result, indicating the actual amount of storage space available for your data after RAID overhead.
• Raw Storage (TB): The total combined capacity of all your drives before any RAID configuration is applied.
• Redundancy Overhead (TB): The amount of storage capacity dedicated to data protection (parity or mirroring) by your chosen RAID type.
• Fault Tolerant Drives: The number of drives that can fail without causing data loss.
• Total Estimated Cost: The approximate total cost of the hard drives based on your input.

Decision-Making Guidance:

Use the results from the Synology Storage Calculator to make informed decisions. If usable storage is too low, consider more drives or larger drives. If fault tolerance is insufficient, explore RAID 6 or SHR-2. Balance your needs for capacity, performance, and data protection against your budget.

Key Factors That Affect Synology Storage Calculator Results

Understanding the variables that influence your Synology Storage Calculator results is crucial for effective NAS planning:

• Number of Drives: More drives generally mean more raw capacity and, depending on the RAID type, more usable storage. However, it also increases power consumption and potential points of failure.
• Individual Drive Size: Larger drives directly increase both raw and usable capacity. It’s often more cost-effective to use fewer, larger drives than many smaller ones, especially for RAID types with fixed parity overhead (e.g., RAID 5/SHR-1).
• RAID Type Selection: This is the most impactful factor. RAID 0 offers maximum capacity but no redundancy. RAID 1, 5, 6, 10, SHR-1, and SHR-2 all sacrifice some capacity for data protection, with varying levels of fault tolerance and performance characteristics.
• Synology Hybrid RAID (SHR) vs. Traditional RAID: SHR is Synology’s proprietary RAID management system. It’s more flexible, allowing for mixed drive sizes and optimizing usable capacity, especially when upgrading drives incrementally. For same-sized drives, SHR-1 behaves like RAID 5, and SHR-2 like RAID 6.
• Future Expansion Needs: Consider your data growth rate. Planning for future expansion by leaving empty bays or choosing a RAID type that allows for easy drive upgrades (like SHR) can save significant effort and cost down the line.
• Budget Constraints: The cost of hard drives can be substantial. Balancing desired capacity and redundancy with your budget is a practical consideration. The optional cost per drive input in our Synology Storage Calculator helps with this.

Frequently Asked Questions (FAQ)

Q: What is the difference between raw storage and usable storage?

A: Raw storage is the total combined capacity of all your hard drives. Usable storage is the actual space available for your data after the RAID configuration has reserved space for redundancy (parity or mirroring).

Q: Why does SHR-1 with 2 drives only give me the capacity of one drive?

A: With two drives, SHR-1 (like RAID 1) mirrors the data across both drives, providing 1-disk redundancy. This means one drive’s capacity is used for your data, and the other is a copy, resulting in usable capacity equal to one drive’s size.

Q: Can I mix different sized drives in a Synology NAS?

A: Yes, Synology Hybrid RAID (SHR) is specifically designed to optimize usable capacity when mixing drives of different sizes. Traditional RAID types (RAID 0, 1, 5, 6, 10) will typically limit all drives to the size of the smallest drive in the array.

Q: What is the minimum number of drives for each RAID type?

A: RAID 0 and RAID 1 require at least 2 drives. RAID 5 and SHR-1 require at least 2 drives (though 3+ is recommended for RAID 5 to be effective). RAID 6 and SHR-2 require at least 3 drives (though 4+ is recommended for RAID 6). RAID 10 requires at least 4 drives (in even numbers).

Q: How does the Synology Storage Calculator handle drive failures?

A: The calculator shows “Fault Tolerant Drives,” which indicates how many drives can fail in your chosen RAID configuration before data loss occurs. This is a key metric for data redundancy planning.

Q: Is the estimated cost accurate?

A: The estimated cost is based on the “Cost per Drive” you input. It’s an approximation for budgeting purposes and does not include the cost of the NAS unit itself, shipping, or other accessories.

Q: Why is my usable storage less than expected even with SHR?

A: Even with SHR, some capacity is always reserved for redundancy. If you have mixed drive sizes, SHR will try to maximize usable space, but there will still be an overhead. Ensure you understand the redundancy level (SHR-1 for 1-disk, SHR-2 for 2-disk) you’ve selected.

Q: Should I always choose the RAID type with the highest fault tolerance?

A: Not necessarily. Higher fault tolerance (e.g., RAID 6, SHR-2) comes at the cost of reduced usable capacity. You need to balance your data’s criticality with your storage needs and budget. For critical data, higher fault tolerance is recommended.

Related Tools and Internal Resources

• Understanding NAS RAID Types: Dive deeper into the technical details and performance implications of various RAID configurations.
• Comprehensive Data Backup Strategies: Learn about different backup methods to complement your NAS redundancy.
• Synology NAS Best Practices Guide: Optimize your Synology NAS for performance, security, and longevity.
• Advanced RAID Level Explanations: A more in-depth look at how RAID levels work and their specific applications.
• Choosing the Right Hard Drives for Your NAS: Tips on selecting reliable and suitable drives for your Synology system.
• Cloud vs. Local Storage Comparison: Evaluate the pros and cons of cloud storage versus a local NAS solution.