Why is VM needed?

Virtual Machines (VMs) have become an essential part of computing infrastructure for many organizations. A VM is an emulation of a computer system that runs on top of a physical machine. It consists of a virtual processor, memory, storage, and networking resources. VMs provide numerous benefits over physical hardware:

Why is VM needed?

Key benefits of VMs:

  • Cost savings – Multiple VMs can run on the same physical server leading to higher utilization and reduced hardware costs.
  • Isolation – VMs provide isolated environments for running applications leading to improved security and stability.
  • Portability – VMs can be easily moved between physical servers with no application downtime.
  • Disaster Recovery – VMs can be backed up and replicated for quick recovery in case of outages.
  • Testing and Development – VMs provide disposable environments for testing code and infrastructure changes.

Despite these advantages, organizations still have to carefully consider if and when VMs are appropriate. The decision depends on the specific goals and constraints of the workload. This article provides an in-depth look at the key scenarios where deploying VMs provides strong benefits.

VMs for Infrastructure Consolidation

A major driver for VM adoption is infrastructure consolidation. Server sprawl leads to underutilized resources and management headaches. VMs allow consolidation of multiple applications onto shared hardware.

For example, an organization may have separate physical servers for web, application, database and file services. Migrating these workloads into VMs enables running them together on high-end servers with abundant cores, memory and storage.

Consolidation provides the following advantages:

  • Reduced hardware costs by lowering the number of servers.
  • Streamlined and automated management when deployed at scale.
  • Improved resource utilization since resources can be allocated dynamically.
  • Consistent environment for applications simplified by virtual networks and storage.
  • Availability benefits from centralized spare capacity and failover.

The ability to run heterogeneous workloads together is a key advantage of consolidation with VMs. Resources such as storage and backup systems can be shared across applications.

However, if workloads have stringent performance, security or compliance requirements, consolidation may not be feasible. The needs of applications must take priority over optimization of infrastructure.

Proper planning and testing is vital prior to consolidating applications onto shared VMs. Performance benchmarks before and after migration will identify any bottlenecks. Monitoring post-deployment ensures availability and user experience is not compromised.

VMs for Application Isolation

VMs provide strong isolation between applications leading to improved security and stability. The hypervisor restricts access between VMs. So compromises, crashes or infections in one VM are contained.

For multi-tenant applications, deploying separate VMs for each tenant isolates code, data and traffic. This prevents noisy neighbor issues where one tenant may overload resources and affect others on the same server.

Regulated workloads often require physical separation for compliance. Healthcare, financial or government applications may mandate isolation to pass audits. VMs provide the necessary segregation while still residing on shared infrastructure.

Developers working on critical systems gain assurance from sandboxed environments. accidental errors or experiments on personal VMs cannot affect production servers. Unique data sets and configurations aid testing and debugging.

However, VMs do not fully isolate at the hardware layer. Vulnerabilities in the hypervisor or physical hosts can still lead to breaches across VMs. Network attacks may target common virtual switches.

So VMs combined with micro-segmentation, encryption and hardened hosts achieve defense-in-depth. The additional cost and complexity of multiple VMs must be weighed against the level of security mandated. Streamlined approaches such as containers may suit applications with moderate isolation needs.

VMs for Disaster Recovery

VMs simplify disaster recovery (DR) by providing portable workloads that can be replicated remotely. Orchestration platforms automate failover so VMs can be brought up at alternate sites in case of outages.

A VM-based DR architecture provides:

  • Backup VMs ready to take over production load during outages.
  • Periodic DR testing by failing over to isolated environments.
  • Orchestrated failover and failback workflows for automation.
  • Flexibility to adjust resource allocation for VMs post-failover.
  • Consistency across production and DR sites using replicated VMs.
  • Cost savings compared to provisioning idle DR hardware.

However, VM replication requires low latency, high bandwidth links between datacenters. Change rate limits and lag between sites should be accounted for.

Storage heavy workloads may be constrained by network bandwidth during initial and ongoing replication. Applications with extreme performance and uptime needs may still require purpose-built DR infrastructure.

A combination of data replication, backup and disaster tolerant hardware maximizes availability. The recovery time and data loss for VM-based DR should be analyzed before relying solely on virtualized workloads.

VMs for Development and Testing

Software developers working on rapidly evolving applications rely on VMs for efficient coding and testing. VMs provide isolated environments that facilitate:

  • Faster build times – VMs avoid time consuming hardware provisioning. Developers instantiate readymade templates with configured tools and dependencies.
  • Effective utilization – Development clusters accommodate fluctuating workloads by dynamically spinning up and down VMs.
  • Reproducible environments – Golden image templates guarantee consistent OS, libraries, configs across developer VMs.
  • Separation of concerns – Components like web, app, and database tiers run isolated in separate VMs during development.
  • Safer experimentation – Developers take risks and try out code changes on personal VMs without destabilizing shared infrastructure.

On the other hand, slower storage and networking compared to physical hardware delays debugging timing issues. Slow build pipelines hamper developer productivity and velocity during coding.

Limited snapshot retention and lack of linked clones on some hypervisors reduce efficiency of managing multiple VM environments per developer. Automation and infrastructure as code minimize these overheads of working with VMs.

Key Takeaways

  • Consolidation with VMs reduces hardware costs and increases utilization. But existing performance and security controls should not be compromised.
  • VMs isolate applications leading to improved stability and security. However, physical separation may still be required for highly regulated workloads.
  • VM replication enables cost-effective disaster recovery. But recovery requirements should be validated thoroughly before replacing purpose-built DR infrastructure.
  • Developers harness VMs for efficient coding and testing. Automation addresses management overheads and constraints posed by virtualized environments.

In summary, VMs provide significant advantages but should be deliberately aligned with workload requirements. Organizations must balance benefits against costs like added complexity and performance overheads.


Virtual machines are a foundational technology that brings significant benefits like cost savings, flexibility and isolation. However, VMs also introduce tradeoffs that may not suit every application. The merits of VMs should be analyzed keeping in mind performance constraints, security mandates and availability needs of workloads.

With careful planning and validation, most applications can benefit from running on shared, virtualized infrastructure. VMs have unlocked innovation in computing by powering agile infrastructure and enabling cloud platforms. But legacy systems with stringent uptime and latency requirements may need continued investment in physical infrastructure.

As applications move to the cloud, VMs provide the guardrails for both portability and control. Organizations gain scalability and reliability from cloud vendors leveraging VMs under the hood. Meanwhile, critical in-house applications can also be gradually migrated to VMs while maintaining security and visibility.

VMs will continue to bridge the gap between old and new – allowing organizations to reap benefits of cloud without having to replatform applications overnight. With thoughtful deployment aligned to use cases, VMs deliver efficiency and flexibility to power modern IT.

Frequently Asked Questions

Q: What are the main advantages of VMs?
A: The main advantages of VMs are cost savings from consolidation, isolation between workloads, portability across servers and simplified disaster recovery.

Q: When does consolidating via VMs make sense?
A: Consolidation with VMs works best when applications have dynamic or fluctuating resource needs and can share backend resources like storage and networking.

Q: What are the downsides to consolidating via VMs?
A: Potential downsides are reduced performance from resource contention, compromised security from sharing a hypervisor and hardware dependence that reduces portability.

Q: How do VMs improve application security?
A: VMs isolate applications via the hypervisor and restrict lateral movement between workloads in case of compromise. This improves overall security.

Q: When does application isolation via VMs not help security?
A: Threats that exploit the hypervisor itself or underlying hardware vulnerabilities can still impact VMs. So physical separation may still be needed for highly sensitive data.

Q: How do VMs simplify disaster recovery?
A: VMs enable replicating entire application stacks to DR sites and automating failover. This avoids manual rebuild and complex orchestration.

Q: When may VMs not suffice for disaster recovery?
A: For extreme uptime needs under minutes, low RPO and RTO, purpose-built DR infrastructure with continuous replication may be necessary.

Q: How do developers use VMs during application development?
A: Developers use VMs for isolated testing environments, quicker build times via templates and safely experimenting via snapshots and clones.

Q: What are challenges developers face when using VMs?
A: Storage and networking performance overheads, snapshot management complexity and slower build pipelines compared to physical hardware.

Q: How does automation help tackle VM management complexity?
A: Infrastructure as code, image templates and configuration management simplify provisioning and maintaining development VM environments.

Q: Should legacy applications be migrated to VMs?
A: Legacy apps with stringent uptime/performance needs or complex dependencies may be hard to migrate to VMs. Containers or physical hosts may suit them better.

Q: When might applications still need physical infrastructure?
A: Extremely high throughput apps, low latency workloads, or highly regulated environments may still call for physical servers due to security and performance needs.

Q: Do VMs fully abstract underlying hardware?
A: No, VMs are still tied to physical resources which introduces constraints. Total abstraction is only possible in serverless computing.

Q: What VM skills are most important for IT teams?
A: Skills in virtualization management, capacity planning, performance monitoring, automation and infrastructure as code maximize benefits from VMs.

Q: How do VMs impact business continuity and disaster recovery plans?
A: VM portability enables new DR strategies like active-active sites and rapid failover. But DR/BC processes must account for replication lag.

Q: When does using VMs increase security risks?
A: A compromised hypervisor allows VMs to be bypassed. Careless network configuration exposes virtual networks to sniffing.

Q: Can VMs provide complete isolation for secure workloads?
A: Not without additional safeguards. Use encryption, microsegmentation, and securing the physical infrastructure for stringent isolation needs.

Q: What are best practices for performance when running applications in VMs?
A: Choose performant hypervisor and hardware, isolate heavy workloads, provide guaranteed resources, optimize drivers and use VM-centric monitoring.

Q: How has VM adoption changed IT organizational structure?
A: IT teams have specialized into roles like SMEs for virtualization management and automation. Shared VM infrastructure needs centralized ops.


In summary, virtual machines provide substantial efficiency and flexibility benefits for many workloads, but should be adopted deliberately based on specific application architectures and business requirements. As VM technology continues maturing, even more workloads can potentially be virtualized, enabling agility and cost savings while still retaining security and performance. But sensitive applications will likely require careful isolation at multiple layers beyond just the virtualization abstraction. With infrastructure trends like hybrid cloud and edge computing gaining steam, VMs will remain a crucial part of the IT landscape for the foreseeable future.


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