The digital landscape thrives on efficient and scalable infrastructure, and at the heart of this lies the cloud virtual private server (VPS). Cloud VPS hosting offers a compelling blend of control, flexibility, and cost-effectiveness, making it a popular choice for businesses and individuals alike. This guide delves into the intricacies of cloud VPS servers, exploring their capabilities, deployment strategies, and the critical considerations for successful implementation.
From understanding the fundamental differences between cloud VPS, dedicated servers, and shared hosting to navigating the diverse offerings of major cloud providers like AWS, Azure, and Google Cloud, we’ll equip you with the knowledge to make informed decisions. We’ll cover crucial aspects such as server sizing, security best practices, cost optimization, and troubleshooting common issues, empowering you to harness the full potential of cloud VPS technology.
Defining Cloud VPS Server Hosting
Cloud VPS (Virtual Private Server) hosting offers a scalable and cost-effective solution for businesses and individuals needing more control and resources than shared hosting provides, but without the commitment and expense of a dedicated server. It essentially virtualizes a dedicated server’s resources, allowing multiple users to share the underlying physical hardware while enjoying isolated environments.Cloud VPS servers are built upon virtualization technology, creating isolated virtual machines (VMs) on a physical server.
Each VM has its own dedicated resources, including CPU cores, RAM, storage, and bandwidth, mimicking the functionality of a dedicated server but at a fraction of the cost. The operating system, applications, and data are completely separate from other VMs on the same physical server, ensuring security and preventing resource conflicts. The cloud provider manages the underlying infrastructure, freeing users from hardware maintenance and updates.
Cloud VPS versus Dedicated Server
A cloud VPS differs significantly from a dedicated server. A dedicated server provides the user with exclusive access to an entire physical machine. This offers maximum control and performance, but also carries higher costs and requires more technical expertise for maintenance. In contrast, a cloud VPS shares the underlying physical hardware with other users but provides isolated resources and environments, offering a balance between cost, control, and performance.
The key difference lies in the level of resource isolation and the management responsibilities; dedicated servers offer complete control but higher costs and maintenance burden, while cloud VPS offers a balance between cost, control and management responsibility.
Cloud VPS versus Shared Hosting
Shared hosting places multiple websites on a single server, sharing resources like CPU, RAM, and bandwidth. This is the most affordable option, but it comes with limitations in terms of performance, security, and control. If one website experiences high traffic, it can impact the performance of other websites on the same server. Cloud VPS hosting, on the other hand, provides dedicated resources, ensuring consistent performance even under heavy load.
It offers better security as each VPS is isolated, preventing one user’s issues from affecting others. While shared hosting is ideal for basic websites with low traffic, a cloud VPS is better suited for resource-intensive applications, websites requiring more control, and businesses needing scalability and reliability.
Cloud Platforms Offering VPS Services
Several major cloud platforms offer VPS services, each with its own strengths and weaknesses. Amazon Web Services (AWS) provides a comprehensive suite of VPS solutions through its Elastic Compute Cloud (EC2), known for its extensive features and global reach. Microsoft Azure offers a similar range of VPS options with strong integration with other Microsoft services. Google Cloud Platform (GCP) is another major player, offering Compute Engine, a scalable and highly performant VPS service.
Other notable providers include DigitalOcean, Vultr, and Linode, each catering to different needs and preferences, often focusing on ease of use and developer-friendly interfaces. The choice of platform often depends on specific requirements, existing infrastructure, and budget considerations. For example, a company already heavily invested in the Microsoft ecosystem might prefer Azure for seamless integration.
Choosing the Right Cloud VPS Server
Selecting the ideal cloud VPS server involves careful consideration of various factors to ensure optimal performance and cost-effectiveness for your specific needs. A well-informed choice can significantly impact your application’s speed, reliability, and overall success. This section guides you through the process of choosing the right VPS, covering crucial aspects from pricing models to performance monitoring.
Cloud VPS Pricing Models
Understanding the different pricing models offered by various cloud VPS providers is essential for budget planning. Providers typically offer various pricing plans based on resource allocation (RAM, CPU, storage) and features. The following table provides a comparison, though specific pricing varies and should be verified directly with each provider. Remember that pricing often changes, so always check the provider’s website for the most up-to-date information.
| Provider | Pricing Plan (Example) | Resources (RAM, CPU, Storage) | Features |
|---|---|---|---|
| Amazon Web Services (AWS) | t2.micro (Pay-as-you-go) | 1GB RAM, 1 vCPU, 8GB SSD | Elastic Block Storage (EBS), Elastic IP, basic networking |
| Google Cloud Platform (GCP) | e2-micro (Sustained Use Discount) | 1GB RAM, 1 vCPU, 25GB Persistent Disk | Cloud Storage, Cloud SQL, managed instance groups |
| Microsoft Azure | B1s (Pay-as-you-go) | 1GB RAM, 1 vCPU, 30GB Disk | Azure Blob Storage, Azure SQL Database, Virtual Network |
| DigitalOcean | Basic Droplet (Hourly billing) | 1GB RAM, 1 vCPU, 25GB SSD | One-click apps, block storage, networking features |
Factors to Consider When Selecting a VPS Provider
Several key factors influence the selection of a suitable VPS provider. These considerations directly impact performance, security, and overall cost-efficiency.Location plays a crucial role in minimizing latency for users accessing your application. Choosing a provider with servers geographically closer to your target audience ensures faster loading times and a better user experience. Security is paramount; selecting a provider with robust security features, such as DDoS protection, regular security updates, and strong encryption, is critical to safeguarding your data and applications.
Scalability is equally important; the ability to easily increase or decrease resources as your needs change prevents overspending and ensures your application can handle fluctuating demands. Finally, responsive and reliable support is essential, particularly during critical situations. Look for providers offering various support channels (e.g., email, phone, chat) and with a proven track record of helpful and timely assistance.
Key Performance Indicators (KPIs) for Optimal VPS Performance
Monitoring key performance indicators is crucial for maintaining optimal VPS performance. Regular monitoring helps identify potential issues early, preventing performance degradation and ensuring application stability.Key KPIs include CPU utilization, memory usage, disk I/O, network latency, and uptime. Consistent monitoring of these metrics allows for proactive adjustments and resource optimization. For example, consistently high CPU utilization might indicate a need for a more powerful VPS, while low disk I/O might suggest optimization opportunities in database queries.
Regular monitoring tools and alerts can significantly assist in identifying and addressing these issues promptly.
Best Practices for Sizing a VPS Server
Accurately sizing your VPS server based on projected needs is vital for cost optimization and performance. Over-provisioning leads to wasted resources and unnecessary expense, while under-provisioning can result in performance bottlenecks and application instability.Begin by estimating the expected traffic, resource consumption, and future growth of your application. Consider factors such as the number of concurrent users, database size, and application resource requirements.
Start with a smaller VPS and scale up as needed. This approach allows for flexibility and cost optimization. For example, a small e-commerce website might initially require a basic VPS, but as it grows, it can be scaled to a larger instance with more resources. Regular monitoring of KPIs will help determine when and how to scale your VPS.
Setting Up and Managing a Cloud VPS Server
Successfully deploying and managing a cloud VPS involves several key steps, from initial server configuration to ongoing maintenance and security. This section details the practical aspects of setting up a basic web server, implementing robust security measures, managing storage and backups, and addressing common troubleshooting issues. Understanding these processes is crucial for ensuring your VPS operates efficiently and securely.
Deploying a Basic Web Server on a Cloud VPS
Deploying a basic web server, such as Apache or Nginx, on a cloud VPS typically involves several steps. First, you’ll connect to your server via SSH using a secure terminal application. Then, you’ll update the system’s package manager (e.g., apt for Debian/Ubuntu, yum for CentOS/RHEL) to ensure you have the latest software versions. Next, you’ll install the web server software itself, followed by configuring the server to listen on the appropriate port (typically port 80 for HTTP and port 443 for HTTPS).
Finally, you’ll test the server by accessing its IP address or domain name in a web browser. This process may vary slightly depending on your chosen operating system and web server software. For example, installing Apache on Ubuntu involves using the command `sudo apt update && sudo apt install apache2`.
Configuring Security Measures for a Cloud VPS
Security is paramount when managing a cloud VPS. Implementing robust security measures is essential to protect your server and data from unauthorized access and malicious attacks. This involves several crucial steps. First, configuring a firewall to restrict access to only necessary ports is critical. For example, you might allow SSH access (port 22) only from specific IP addresses and block all other incoming connections.
Second, securing SSH access is vital, often achieved through strong passwords, SSH key authentication, and limiting login attempts. Third, regularly updating the operating system and all installed software patches vulnerabilities and keeps your server secure. Finally, implementing intrusion detection systems can help monitor for suspicious activity.
Managing Storage and Backups on a Cloud VPS
Effective storage and backup management are critical for data protection and server stability. Cloud VPS providers often offer various storage options, such as local storage (SSD or HDD), network-attached storage (NAS), or cloud storage services. Understanding the different storage types and their performance characteristics is important for choosing the right option for your needs. Regular backups are essential for data recovery in case of hardware failure, accidental deletion, or cyberattacks.
A robust backup strategy should involve frequent backups to a separate location, such as a cloud storage service or an external drive, using tools like rsync or specialized backup software. Testing the backup and restore process regularly is vital to ensure its effectiveness.
Troubleshooting Common Scenarios
Troubleshooting is an inevitable part of managing a cloud VPS. Common issues include network connectivity problems, server crashes, and application errors. Network connectivity problems can often be resolved by checking network configurations, DNS settings, and firewall rules. Server crashes might require investigating system logs for error messages, checking resource usage (CPU, memory, disk space), and restarting the server or affected services.
Application errors usually necessitate checking application logs, reviewing configuration files, and potentially reinstalling or updating the application. Effective troubleshooting involves systematic investigation, using available tools and resources, and seeking assistance from the VPS provider or online communities when necessary. For instance, a common error message like “Connection refused” often points to a firewall issue or a service not running.
Analyzing server logs is a key step in diagnosing most problems.
Applications and Use Cases of Cloud VPS Servers
Cloud VPS servers offer a versatile and scalable solution for a wide range of applications, providing businesses and individuals with the flexibility and control needed to manage their online presence and digital infrastructure effectively. Their ability to offer dedicated resources within a shared environment makes them a compelling alternative to both dedicated servers and shared hosting.Cloud VPS servers are well-suited for various applications due to their customizable resource allocation and manageable costs.
This allows users to tailor their server resources to specific application demands, optimizing performance and cost-effectiveness. The inherent scalability also allows for easy expansion as application needs grow.
Web Hosting
Cloud VPS servers are an excellent choice for web hosting, particularly for websites with moderate to high traffic volumes or those requiring specific software configurations. They offer a balance between the affordability of shared hosting and the control and performance of dedicated servers. A VPS provides dedicated resources, ensuring consistent performance even during traffic spikes, unlike shared hosting which can experience slowdowns under heavy load.
The ability to install custom software and configurations further enhances their suitability for websites with unique requirements. For example, an e-commerce site with high transaction volume would benefit from the dedicated resources and performance stability a VPS offers, ensuring a smooth customer experience.
Database Hosting
Hosting databases on a cloud VPS server offers several advantages, including dedicated resources for optimal performance and enhanced security. The isolation of resources prevents resource contention issues that can occur in shared hosting environments. Furthermore, the ability to customize the operating system and database software allows for fine-tuned optimization. A company managing a large customer database would appreciate the performance and security benefits of a VPS, allowing for efficient data management and protection against unauthorized access.
The scalability of a cloud VPS is also beneficial as the database grows.
Game Servers
Cloud VPS servers are frequently utilized for hosting game servers, particularly for multiplayer online games. The dedicated resources ensure low latency and consistent performance, crucial for a smooth and enjoyable gaming experience. The ability to scale resources up or down based on player numbers allows for efficient cost management, paying only for the resources actually consumed. A popular indie game developer might leverage a cloud VPS to host its game server, scaling resources up during peak playtime and down during off-peak hours to optimize costs.
Development and Testing Environments
Cloud VPS servers provide ideal environments for software development and testing. Developers can create isolated environments to test applications without affecting production systems. This isolation ensures that testing does not disrupt live services, while the ability to easily create and destroy instances allows for rapid iteration and experimentation. A software development team might use several VPS instances to simulate different production environments for testing purposes, replicating real-world conditions before deployment.
Advantages and Disadvantages of Using Cloud VPS Servers for Specific Applications
The suitability of a cloud VPS depends on the specific application and its resource requirements.
It’s important to weigh the advantages and disadvantages before selecting a cloud VPS for a particular application. Below is a table summarizing these considerations for various use cases:
| Application | Advantages | Disadvantages |
|---|---|---|
| Web Hosting | Dedicated resources, scalability, customization, good performance | Potentially higher cost than shared hosting, requires some technical expertise |
| Database Hosting | Enhanced security, dedicated resources, optimal performance, scalability | Requires database administration knowledge, potential cost depending on database size |
| Game Servers | Low latency, consistent performance, scalability, cost-effective scaling | Requires game server software configuration, potential network configuration complexity |
| Development/Testing | Isolated environments, easy creation/destruction of instances, cost-effective | Requires some technical expertise to set up and manage environments |
Scaling Web Applications with Cloud VPS Servers
Cloud VPS servers play a crucial role in scaling web applications. As an application grows, its resource needs increase. A cloud VPS allows for easy scaling by simply upgrading the server’s resources or adding more VPS instances to distribute the load. This horizontal scaling is far more efficient and cost-effective than vertical scaling (upgrading a single, powerful server).
For instance, a rapidly growing e-commerce platform could initially use a single VPS. As traffic increases, they can add more VPS instances to distribute the load, ensuring consistent performance and preventing outages. This horizontal scalability is a key advantage of cloud VPS servers, allowing businesses to adapt to fluctuating demands without significant infrastructure changes or downtime.
Security Considerations for Cloud VPS Servers
Securing your cloud VPS server is paramount to protecting your data and applications. A compromised server can lead to data breaches, financial losses, and reputational damage. Proactive security measures are essential to mitigate these risks and ensure the ongoing reliability and integrity of your server environment. This section details key security considerations and best practices for safeguarding your cloud VPS.
Common Security Threats and Mitigation Strategies
Understanding potential threats and implementing effective mitigation strategies is crucial for maintaining a secure cloud VPS. The following table Artikels common threats, associated vulnerabilities, mitigation strategies, and illustrative examples.
| Threat | Vulnerability | Mitigation Strategy | Example |
|---|---|---|---|
| Malware Infection | Outdated software, weak passwords, unpatched vulnerabilities | Regular security updates, strong passwords, intrusion detection systems (IDS), antivirus software | A server infected with ransomware, encrypting all files and demanding a ransom. This could have been prevented by regularly updating the operating system and applications, and using a strong, unique password. |
| Denial of Service (DoS) Attacks | Open ports, lack of rate limiting | Firewall configuration, rate limiting, DDoS protection services | A flood of malicious traffic overwhelms the server, making it inaccessible to legitimate users. A robust firewall and DDoS protection service can mitigate this by blocking malicious traffic and absorbing the attack. |
| Unauthorized Access | Weak or default passwords, insecure SSH access, lack of two-factor authentication | Strong passwords, SSH key-based authentication, two-factor authentication (2FA), regular password changes | An attacker gains access to the server using a weak password found through brute-force attacks. Implementing 2FA and strong passwords significantly reduces this risk. |
| Data Breaches | Unencrypted data, lack of data encryption at rest and in transit | Data encryption at rest (e.g., using LUKS for disk encryption) and in transit (e.g., using HTTPS), regular data backups | Sensitive customer data is stolen due to a lack of encryption. Encrypting data both at rest and in transit prevents unauthorized access even if the server is compromised. |
| Insider Threats | Lack of access control, inadequate monitoring | Principle of least privilege, access logs, regular security audits | An employee with excessive privileges unintentionally or maliciously compromises the server. Implementing the principle of least privilege and regular security audits helps minimize this risk. |
Regular Security Updates and Patching
Regular security updates and patching are fundamental to maintaining a secure cloud VPS. Software vulnerabilities are constantly being discovered, and attackers actively exploit these weaknesses. Applying updates promptly patches these vulnerabilities, reducing the server’s attack surface and minimizing the risk of compromise. This includes updating the operating system, applications, and all installed software packages. A schedule should be established for regular patching, prioritizing critical security updates.
Automated update mechanisms, where available, can significantly streamline this process.
Secure Configurations for Common Services
Implementing secure configurations for common services running on a cloud VPS is vital. This involves configuring firewalls to allow only necessary traffic, disabling unnecessary services, and using strong authentication mechanisms.For example, a secure SSH configuration would involve disabling password authentication in favor of key-based authentication, limiting login attempts, and regularly changing SSH keys. For web servers (like Apache or Nginx), using HTTPS with a valid SSL/TLS certificate is essential for encrypting communication between the server and clients.
Database servers (like MySQL or PostgreSQL) should be configured with strong passwords, limited user accounts, and regular backups.
Access Control and User Permissions
Access control and user permissions are critical for enhancing security. The principle of least privilege dictates that users should only have the necessary access rights to perform their tasks. This limits the potential damage from a compromised account. Regularly reviewing and adjusting user permissions, as well as implementing robust access logging and monitoring, allows for the early detection of suspicious activity.
Multi-factor authentication should be employed wherever possible to add an extra layer of security.
Cost Optimization Strategies for Cloud VPS Servers
Managing cloud VPS costs effectively is crucial for maintaining a healthy budget. Uncontrolled spending can quickly escalate, impacting profitability. This section Artikels several strategies to optimize your cloud VPS expenses, ensuring you get the best value for your investment. These strategies focus on resource utilization, instance selection, and leveraging pricing models offered by cloud providers.
Right-Sizing Instances
Choosing the appropriate instance size is paramount for cost optimization. Over-provisioning resources leads to unnecessary expenditure, while under-provisioning can result in performance bottlenecks. Analyzing your application’s resource requirements – CPU, RAM, storage, and network bandwidth – is vital. Tools provided by cloud providers often offer detailed usage metrics, enabling you to identify periods of peak and low demand.
Based on this analysis, you can select an instance size that adequately handles peak loads without excessive idle capacity during less demanding periods. For example, if your application experiences significant traffic spikes only during specific hours, consider scaling your instances up during those times and scaling down during off-peak hours, using features like auto-scaling. This dynamic approach ensures optimal resource utilization and minimizes costs.
Utilizing Spot Instances
Spot instances represent a cost-effective alternative to on-demand instances. Cloud providers offer these instances at significantly reduced prices, but with the caveat that they can be reclaimed with short notice. This is because spot instances use spare computing capacity. Therefore, applications that can tolerate interruptions are ideal candidates for spot instances. A well-designed application with robust fault tolerance and automated recovery mechanisms can leverage spot instances for significant cost savings.
For instance, batch processing jobs or less critical background tasks are well-suited for this approach. Carefully planning your application’s architecture and implementing appropriate error handling and recovery strategies are crucial when using spot instances.
Cloud VPS Pricing Models
Cloud providers typically offer various pricing models, each with its own cost implications. Understanding these models is essential for cost-effective deployment. On-demand pricing provides flexibility but can be expensive for long-term deployments. Reserved instances offer significant discounts for committing to a specific instance type and duration. Savings plans provide sustained discounts based on consistent usage over a specified period.
Choosing the right pricing model depends on your application’s needs and predicted usage patterns. For instance, a long-running application with predictable usage would benefit from reserved instances or savings plans, while applications with fluctuating demands might be better suited to on-demand pricing. Careful analysis of your usage patterns and future projections is essential to selecting the most cost-effective model.
Monitoring Resource Usage
Regularly monitoring your VPS’s resource usage is crucial for identifying areas for optimization. Cloud providers typically provide detailed monitoring dashboards that track CPU utilization, memory consumption, disk I/O, and network traffic. By analyzing these metrics, you can pinpoint resource bottlenecks and inefficiencies. For example, consistently high CPU utilization might indicate a need for a more powerful instance or application optimization.
Similarly, low disk I/O might suggest that you are over-provisioning storage. Proactive monitoring enables timely adjustments, preventing unnecessary expenses and ensuring optimal performance. Setting up alerts for critical resource thresholds allows for prompt intervention, preventing potential service disruptions and cost overruns.
Checklist for Reducing Cloud VPS Expenses
Before implementing any cost optimization strategy, it’s beneficial to create a checklist. This ensures that all potential areas for improvement are considered.
- Right-size your instances based on actual resource consumption.
- Explore the use of spot instances for fault-tolerant applications.
- Evaluate different pricing models (on-demand, reserved, savings plans) to identify the most cost-effective option.
- Implement regular monitoring of resource usage to detect and address inefficiencies.
- Utilize cloud provider tools and features for automation and optimization (e.g., auto-scaling).
- Regularly review and eliminate unused resources (e.g., storage, databases).
- Optimize your applications for efficiency to reduce resource demands.
Illustrative Examples of Cloud VPS Server Deployments
Cloud VPS servers offer adaptable solutions for diverse business needs. The following examples illustrate how different organizations can leverage VPS resources to achieve their specific goals, considering factors such as resource allocation, cost, scalability, and security.
Small Business Website Hosting
A small bakery, “Sweet Success,” decides to establish an online presence with a website showcasing its products and taking orders. They choose a cloud VPS with modest specifications: 1 CPU core, 2GB RAM, and 20GB storage. This configuration is sufficient for their initial website traffic and allows for easy scaling as their business grows. The VPS provider offers a pay-as-you-go pricing model, making it cost-effective for Sweet Success, as they only pay for the resources they consume.
Should their website traffic increase significantly during holiday seasons, they can easily upgrade their VPS to a larger configuration with more CPU cores, RAM, and storage within minutes, ensuring smooth website operation even during peak demand. The relatively low cost of entry and the scalability inherent in the cloud environment makes this a financially sound and flexible option for the bakery.
High-Traffic E-commerce Platform
“TechGear,” a rapidly expanding online retailer, requires a robust and scalable infrastructure for its e-commerce platform. Their cloud VPS setup involves multiple interconnected servers, utilizing a load balancer to distribute incoming traffic evenly across the servers. This prevents any single server from becoming overloaded and ensures consistent website performance, even during peak shopping periods like Black Friday. A distributed database system manages product information, customer accounts, and order details, enhancing data availability and reducing the risk of single points of failure.
TechGear implements stringent security measures, including firewalls, intrusion detection systems, and regular security audits, to protect sensitive customer data and prevent cyberattacks. The platform’s architecture is designed to scale horizontally by adding more servers to the load balancer as needed, accommodating significant traffic spikes without compromising performance. They leverage content delivery networks (CDNs) to cache static content closer to users, further enhancing speed and reducing server load.
Cloud-Based Gaming Server
A game development studio launches a massively multiplayer online role-playing game (MMORPG). To host the game’s servers, they utilize a cloud VPS setup tailored for high performance and low latency. The infrastructure includes powerful servers with multiple CPU cores, substantial RAM, and high-bandwidth network connections. The game’s data is stored in a high-performance database optimized for rapid read/write operations, ensuring smooth gameplay for thousands of concurrent users.
The VPS provider offers tools and services for monitoring server performance, managing game updates, and mitigating DDoS attacks, critical considerations for maintaining a stable and secure gaming environment. The scalable nature of the cloud allows the studio to dynamically adjust server resources based on player population fluctuations, ensuring optimal gameplay experiences while efficiently managing costs. Regular backups and disaster recovery plans are in place to minimize downtime and data loss.
Last Point
Mastering cloud VPS server hosting unlocks a world of possibilities for optimizing your online presence and application deployments. By understanding the nuances of choosing the right provider, configuring your server effectively, and implementing robust security measures, you can achieve significant gains in performance, scalability, and cost efficiency. This guide has provided a foundation for your journey; now, it’s time to leverage this knowledge to build and manage your cloud infrastructure with confidence and success.
User Queries
What are the limitations of a cloud VPS?
While offering great flexibility, cloud VPSs can be limited by the underlying hypervisor’s resources. Performance can be impacted by other users on the same physical hardware, although this is generally mitigated by robust virtualization technologies. Complete control over the underlying hardware is also less than with a dedicated server.
How do I choose the right operating system for my cloud VPS?
The optimal operating system depends on your application needs and familiarity. Popular choices include Linux distributions like Ubuntu, CentOS, and Debian, known for their stability and extensive software repositories. Windows Server is another option, particularly suitable for applications requiring a Windows environment. Consider factors such as security updates, community support, and compatibility with your software.
What is the difference between managed and unmanaged VPS hosting?
Managed VPS hosting includes server management services like operating system updates, security patching, and basic technical support. Unmanaged VPS hosting provides the server resources but requires you to handle all aspects of server management. The choice depends on your technical expertise and desired level of hands-on involvement.
Can I migrate my existing website to a cloud VPS?
Yes, migrating your website to a cloud VPS is generally possible. The process involves backing up your website data, setting up your VPS, restoring the backup, and configuring DNS settings to point to the new server. Consider using tools and techniques to minimize downtime during the migration.