Veeam Sizing Calculator 2026 - Plan Your Backup Infrastructure
Calculate Veeam Backup & Replication infrastructure requirements with our advanced sizing calculator for 2026. This free tool helps IT professionals, system administrators, and backup architects accurately determine repository capacity, proxy resources, backup server specifications, and storage requirements for Veeam deployments. Whether you're planning a new Veeam installation or scaling an existing environment, our calculator provides precise sizing recommendations based on official Veeam best practices and industry standards.
Veeam sizing refers to the process of calculating the appropriate infrastructure resources needed to support your Veeam Backup & Replication environment effectively. Proper sizing ensures optimal backup performance, adequate storage capacity, sufficient processing power for backup proxies, and reliable data protection across your virtual, physical, and cloud workloads. Undersized Veeam infrastructure leads to failed backups, long backup windows, and inadequate disaster recovery capabilities.
Accurate Veeam sizing calculations account for multiple factors including the total capacity of virtual machines being protected, daily change rates, compression and deduplication ratios, retention policies, backup job scheduling, and recovery time objectives (RTO). These calculations determine specifications for backup repositories, proxy servers, backup servers, and network bandwidth requirements, ensuring your Veeam environment meets both performance and compliance standards.
## Veeam Sizing Calculator ToolRepository & Infrastructure Sizing
Veeam Sizing Results
Veeam sizing calculations follow industry-standard formulas that account for backup capacity, retention requirements, and infrastructure overhead. The core calculation determines repository capacity based on the source data size, change rate, compression ratio, and retention policy. Additional calculations size backup proxies, backup servers, and network bandwidth requirements.
Repository Capacity Calculation (Reverse Incremental):
\[ C_{\text{repo}} = \left(\frac{D_{\text{total}}}{R_{\text{comp}}}\right) + \left(\frac{D_{\text{total}} \times CR \times (n-1)}{R_{\text{comp}}}\right) + S_{\text{overhead}} \]
Where:
- \(D_{\text{total}}\) = Total source data capacity
- \(R_{\text{comp}}\) = Compression ratio
- \(CR\) = Daily change rate (decimal)
- \(n\) = Number of retention days
- \(S_{\text{overhead}}\) = Overhead space (typically 25% of backup size)
Repository Capacity (Forward Incremental with Weekly Fulls):
\[ C_{\text{repo}} = \left(F_{\text{full}} \times N_{\text{fulls}}\right) + \left(F_{\text{incr}} \times N_{\text{incr}}\right) + S_{\text{overhead}} \]
Where:
- \(F_{\text{full}} = \frac{D_{\text{total}}}{R_{\text{comp}}}\) (Size of full backup)
- \(N_{\text{fulls}}\) = Number of full backups to retain
- \(F_{\text{incr}} = \frac{D_{\text{total}} \times CR}{R_{\text{comp}}}\) (Size of incremental)
- \(N_{\text{incr}}\) = Maximum number of incrementals
\[ \text{Proxy vCPU} = \text{Concurrent Tasks} \times 1 \text{ vCPU per task} \]
\[ \text{Proxy RAM} = \text{Concurrent Tasks} \times 2 \text{ GB per task} + 4 \text{ GB base} \]
| Component | Small (< 500 VMs) | Medium (500-1500 VMs) | Large (> 1500 VMs) |
|---|---|---|---|
| CPU Cores | 4 cores | 8 cores | 16 cores |
| RAM | 8 GB | 16 GB | 32 GB |
| SQL Server Database | SQL Express (< 10 GB) | SQL Standard | SQL Standard/Enterprise |
| Disk Space (C:) | 40 GB | 40 GB | 60 GB |
| vPower NFS | 100 GB | 200 GB | 500 GB |
| Proxy Type | vCPU per Task | RAM per Task | Network |
|---|---|---|---|
| Virtual Appliance Mode | 1 vCPU | 2 GB | 1 Gbps+ |
| Network Mode | 1 vCPU | 2 GB | 10 Gbps recommended |
| Direct SAN Mode | 1 vCPU | 4 GB | N/A (SAN fabric) |
- Enter Total VM Capacity: Input the total capacity in terabytes (TB) of all virtual machines you plan to protect with Veeam Backup & Replication
- Specify Number of VMs: Enter the total count of virtual machines to be backed up, which affects backup server and proxy sizing
- Set Daily Change Rate: Define the percentage of data that changes daily (typical range: 2-10%, use 5% if unknown)
- Choose Compression Ratio: Select conservative (2:1), average (2.5:1), or optimistic (3:1) based on your data types
- Define Retention Period: Enter how many days of backup history to retain (common: 14, 30, or 90 days)
- Select Backup Mode: Choose your backup strategy - reverse incremental or forward incremental with weekly/monthly fulls
- Configure Proxy Tasks: Specify how many concurrent backup tasks your environment requires
- Enable WAN Accelerator: Indicate if WAN acceleration will be used for remote site backups
- Calculate: Click the calculate button to receive comprehensive sizing recommendations
- Review Results: Examine repository capacity, proxy specifications, backup server requirements, and bandwidth estimates
Scenario: 100 VMs, 10 TB total capacity, 5% change rate, 30-day retention
Backup Mode: Reverse Incremental
\[ \text{Full Backup Size} = \frac{10 \text{ TB}}{2} = 5 \text{ TB} \]
\[ \text{Incremental Size} = \frac{10 \times 0.05}{2} = 0.25 \text{ TB per day} \]
\[ \text{Total Incrementals} = 0.25 \times 29 = 7.25 \text{ TB} \]
\[ \text{Repository Capacity} = 5 + 7.25 + (12.25 \times 0.25) = 15.31 \text{ TB} \]
Required Repository: ~16 TB with overhead
Scenario: 500 VMs, 50 TB capacity, 5% change rate, 30-day retention
Backup Mode: Forward Incremental (Weekly Fulls)
\[ \text{Full Backup Size} = \frac{50}{2.5} = 20 \text{ TB} \]
\[ \text{Number of Fulls} = \lceil\frac{30}{7}\rceil = 5 \text{ weekly fulls} \]
\[ \text{Daily Incrementals} = \frac{50 \times 0.05}{2.5} = 1 \text{ TB} \]
\[ \text{Max Incrementals} = 32 \text{ (for 30 days + buffer)} \]
\[ \text{Repository} = (20 \times 5) + (1 \times 32) = 132 \text{ TB} \]
Required Repository: ~165 TB with 25% overhead
Windows Server with ReFS (Resilient File System) provides significant advantages for Veeam repositories:
- Fast Clone Technology: Near-instantaneous creation of synthetic full backups without data movement
- Block Cloning: Saves up to 50% storage space through intelligent block-level deduplication
- Instant Restore: Dramatically faster restore operations using ReFS pointers
- Integrity Streams: Built-in data integrity verification and corruption detection
ReFS Space Savings Calculation:
\[ \text{Actual Space} = \text{Logical Size} \times (1 - \text{Dedup Ratio}) \]
With ReFS block cloning, deduplication ratios of 30-50% are common
Veeam supports object storage repositories for scale-out architectures and cloud-native deployments:
- Amazon S3 and S3-compatible storage
- Azure Blob Storage
- Google Cloud Storage
- On-premises S3-compatible appliances
Backup proxies are the workhorses of Veeam infrastructure, processing data blocks during backup and restore operations. Proper proxy sizing ensures backup windows are met and recovery operations complete quickly.
Proxy Throughput Calculation:
\[ \text{Required Throughput} = \frac{D_{\text{total}}}{\text{Backup Window (hours)}} \]
\[ \text{Proxy Tasks} = \frac{\text{Required Throughput}}{\text{Task Speed}} \]
Task speed varies: Network mode ~200 MB/s, Virtual Appliance ~150 MB/s, Direct SAN ~300 MB/s
| Model | Use Case | Advantages | Considerations |
|---|---|---|---|
| Virtual Appliance | General purpose | Easy deployment, no physical hardware | Moderate performance |
| Network Mode | High-speed networks | Good performance, flexible | Network bandwidth critical |
| Direct SAN | SAN environments | Highest performance, no LAN traffic | Requires SAN access |
| Off-host Backup | Storage snapshots | Zero production impact | Storage array integration needed |
https://www.nist.gov/cyberframework
The official NIST Cybersecurity Framework provides comprehensive guidelines for organizations to manage and reduce cybersecurity risks. Updated for 2026, the framework emphasizes data protection, backup resilience, and recovery capabilities as core components of cyber defense strategy. Essential reading for aligning Veeam deployments with federal security standards.
https://csrc.nist.gov/publications/detail/sp/800-209/draft
NIST Special Publication 800-209 provides comprehensive security recommendations for storage infrastructure including backup systems, data protection, isolation, restoration assurance, and encryption. This federal guideline covers network-attached storage (NAS), storage area networks (SAN), and modern backup architectures essential for Veeam deployment planning in 2026.
WAN accelerators optimize data transfer between sites by reducing bandwidth consumption through advanced caching and compression techniques. Proper WAN accelerator sizing ensures efficient replication to remote sites.
WAN Accelerator Cache Sizing:
\[ \text{Cache Size} = D_{\text{source}} \times 0.10 \]
Minimum: 100 GB, Recommended: 10% of source data size
\[ \text{WAN Accelerator RAM} = 4 \text{ GB base} + (2 \text{ GB per concurrent task}) \]
Determining if your backup window can be met is critical for operational success. The backup window is the time available to complete all backup jobs.
\[ \text{Required Time} = \frac{D_{\text{changed}}}{(\text{Proxy Tasks} \times \text{Task Speed})} \]
\[ D_{\text{changed}} = D_{\text{total}} \times CR \times \frac{1}{R_{\text{comp}}} \]
If Required Time < Available Window, backup window is feasible
Scale-Out Backup Repositories enable capacity and performance scaling by combining multiple repositories into a single logical entity with intelligent data placement policies.
SOBR Performance Tier Sizing:
\[ \text{Performance Tier} = \text{Active Full Backups} + \text{Recent Incrementals} \]
Capacity tier can be object storage for long-term retention at lower cost
Veeam supports immutable backups on compatible storage, protecting against ransomware and malicious deletion. Immutability requires additional planning:
- Linux-based hardened repositories with immutability periods
- Object storage with S3 Object Lock
- Integration with enterprise backup appliances supporting immutability
| Time Period | Expected Growth | Capacity Buffer |
|---|---|---|
| Year 1 | 20-30% | Plan for 150% of current needs |
| Year 2-3 | 40-60% | Plan for 200% of current needs |
| Year 3+ | 80-100% | Plan for modular expansion |
Network bandwidth directly impacts backup performance and window feasibility. Calculate required bandwidth based on data change rate and available backup time.
\[ \text{Required Bandwidth (Mbps)} = \frac{D_{\text{changed}} \times 8}{T_{\text{window}} \times 3600} \]
Where \(D_{\text{changed}}\) is in MB and \(T_{\text{window}}\) is in hours
Add 20-30% overhead for protocol efficiency and concurrent operations
- Test Actual Ratios: Run pilot backups to determine real compression and change rates for your environment
- Size for Growth: Plan repository capacity for 18-24 months to avoid frequent expansions
- Separate Metadata: Use fast storage (SSD) for backup metadata and slower storage for backup data
- Monitor Performance: Use Veeam ONE for ongoing monitoring and capacity planning
- Consider ReFS: Leverage ReFS on Windows repositories for space savings and performance gains
- Plan for Peaks: Size proxies for peak backup load, not just average workload
- Document Assumptions: Record all sizing assumptions for future reference and adjustments
- Implement 3-2-1 Rule: Maintain 3 copies of data, on 2 different media types, with 1 off-site
Proper Veeam sizing ensures successful backup operations, meets recovery time objectives (RTO) and recovery point objectives (RPO), maintains compliance with data retention policies, and provides scalability for future growth. Undersized infrastructure leads to backup failures, incomplete backups, and inadequate disaster recovery capabilities. Oversizing wastes budget on unnecessary resources and increases complexity.
Our Veeam sizing calculator eliminates guesswork by applying industry-standard formulas and best practices from Veeam architects. Whether you're planning a new deployment, scaling an existing environment, or validating vendor proposals, accurate sizing calculations provide confidence that your backup infrastructure will meet operational requirements and protect your organization's critical data assets.
Need more IT infrastructure calculators? Visit OmniCalculator.space for comprehensive free calculators covering storage capacity planning, bandwidth requirements, virtualization sizing, and other essential IT infrastructure tools.