Vocabulary and Glossary
How to Use This Glossary
This glossary contains all the important virtualization terms from Module 4, organized alphabetically for easy reference. Each term includes:
- Definition: What the term means in simple language
- Real-world analogy: A comparison to help you remember and understand
- Example: How you might encounter this in actual work
- Related terms: Other vocabulary that connects to this concept
A
Affinity Rules
Definition: Configuration rules that control which VMs can run together on the same host or must be kept apart Real-world analogy: Like rules in an apartment building - some tenants must live on the same floor (couples), others can't (noisy neighbors) Example: Database server and web server must run on same host (affinity), or primary and backup domain controllers must run on different hosts (anti-affinity) Related terms: DRS, Anti-Affinity, VM Placement
Anti-Affinity Rules
Definition: Rules that prevent specific VMs from running on the same physical host Real-world analogy: Like keeping backup generators in different buildings so one disaster can't disable all backups Example: Primary and secondary email servers configured to never run on the same ESXi host Related terms: Affinity Rules, HA, DRS
B
Ballooning
Definition: A memory management technique where the hypervisor reclaims unused memory from VMs when the host needs more memory Real-world analogy: Like asking hotel guests to use fewer towels when the laundry is backed up Example: When host memory gets low, the balloon driver asks VMs to release memory they're not actively using Related terms: Memory Management, Memory Pressure, Hypervisor
Bare Metal Hypervisor
Definition: A hypervisor that runs directly on physical hardware without an underlying operating system (Type 1) Real-world analogy: Like a building superintendent who lives directly in the building foundation Example: VMware ESXi, Microsoft Hyper-V Server, Citrix XenServer Related terms: Type 1 Hypervisor, ESXi, Hosted Hypervisor
C
Clone
Definition: An exact copy of a virtual machine, including all its files and configurations Real-world analogy: Like making a photocopy of a document - you get an identical duplicate Example: Creating Clone-WebServer-02 from WebServer-01 to add more web server capacity Related terms: Template, Full Clone, Linked Clone
Cluster
Definition: A group of ESXi hosts that work together and share resources Real-world analogy: Like a team of doctors in a hospital who can cover for each other and share equipment Example: A 4-host cluster where VMs can run on any host and move between hosts for maintenance Related terms: HA, DRS, Resource Pool, vMotion
Consolidation Ratio
Definition: The number of virtual machines running per physical host Real-world analogy: Like the occupancy ratio in an apartment building - how many families live in one building Example: A host running 20 VMs has a 20:1 consolidation ratio Related terms: Resource Utilization, Capacity Planning, Overcommitment
D
Datastore
Definition: A storage container where virtual machine files are kept Real-world analogy: Like a large warehouse where different companies store their inventory in separate sections Example: A 2TB NFS datastore storing VM files for 15 different virtual machines Related terms: VMFS, NFS, Storage, Virtual Disk
Distributed Resource Scheduler (DRS)
Definition: VMware technology that automatically balances VM workloads across hosts in a cluster Real-world analogy: Like an intelligent traffic system that automatically routes cars to less congested roads Example: DRS automatically moves VMs from a busy host to a less utilized host to balance performance Related terms: Load Balancing, Cluster, vMotion, Resource Management
Dynamic Memory
Definition: A feature that automatically adjusts the amount of memory allocated to VMs based on actual usage Real-world analogy: Like a flexible workspace that expands or shrinks based on how many people are working Example: A VM starts with 4GB RAM but can grow to 8GB when running memory-intensive applications Related terms: Memory Ballooning, Resource Management, Memory Overcommitment
E
ESXi
Definition: VMware's bare-metal hypervisor that runs directly on server hardware Real-world analogy: Like the foundation and framework of a building that supports all the floors above Example: Dell PowerEdge server running ESXi 8.0 hosting 15 virtual machines Related terms: Hypervisor, vSphere, vCenter, Type 1
Enhanced vMotion Compatibility (EVC)
Definition: A feature that allows vMotion between hosts with different CPU types by masking newer CPU features Real-world analogy: Like using simple language so people from different regions can understand each other Example: Enabling EVC allows moving VMs between Intel Xeon E5 and newer Xeon Silver processors Related terms: vMotion, CPU Compatibility, Migration
F
Full Clone
Definition: A complete, independent copy of a virtual machine that uses its own disk space Real-world analogy: Like building an identical house on a different lot - completely independent Example: Creating a production VM as full clone of a tested development VM Related terms: Clone, Linked Clone, Template, Storage
Fault Tolerance (FT)
Definition: VMware technology that creates a live shadow copy of a VM on another host for zero-downtime protection Real-world analogy: Like having a perfect synchronized backup dancer who can take over instantly if the main dancer stumbles Example: Critical payment processing VM running with FT to ensure zero downtime during host failures Related terms: HA, vLockstep, Zero Downtime, Availability
G
Guest OS
Definition: The operating system running inside a virtual machine Real-world analogy: Like the interior design and furniture inside an apartment Example: Windows Server 2019 running as the guest OS inside a VMware virtual machine Related terms: Virtual Machine, Host OS, VMware Tools
Guest Additions/Tools
Definition: Special software installed inside VMs to improve performance and enable advanced features Real-world analogy: Like smart home features that help an apartment work better with the building's systems Example: VMware Tools enabling copy/paste between host and guest, time synchronization, and better graphics Related terms: VMware Tools, Integration Services, Performance
H
High Availability (HA)
Definition: A cluster feature that automatically restarts VMs on other hosts when a host fails Real-world analogy: Like having backup power generators that automatically start when main power fails Example: When ESXi host fails, HA automatically restarts all VMs on surviving cluster hosts within 2-5 minutes Related terms: Cluster, Failover, Fault Tolerance, Availability
Host OS
Definition: The operating system running on the physical computer (used with Type 2 hypervisors) Real-world analogy: Like the building management system that the apartment building runs on Example: Windows 10 running VMware Workstation to host virtual machines Related terms: Type 2 Hypervisor, Guest OS, Hosted Virtualization
Hosted Hypervisor
Definition: A hypervisor that runs on top of an existing operating system (Type 2) Real-world analogy: Like a property management company that manages buildings from a separate office Example: VirtualBox running on Windows 10 to create virtual machines for testing Related terms: Type 2 Hypervisor, VMware Workstation, VirtualBox
Hypervisor
Definition: The software layer that creates and manages virtual machines Real-world analogy: Like a building manager who allocates apartments and manages shared resources Example: VMware ESXi managing 20 virtual machines on a single physical server Related terms: VMM, Virtual Machine Monitor, ESXi, Type 1, Type 2
I
Infrastructure as a Service (IaaS)
Definition: Cloud computing service that provides virtualized computing resources over the internet Real-world analogy: Like renting office space where you get the building and utilities, but bring your own furniture and staff Example: Using AWS EC2 instances or Microsoft Azure VMs instead of buying physical servers Related terms: Cloud Computing, Public Cloud, EC2, Azure
L
Linked Clone
Definition: A copy of a VM that shares virtual disks with the original VM to save storage space Real-world analogy: Like two apartments sharing the same basement storage area Example: Creating multiple test VMs as linked clones from a master template, each using only 2GB instead of 40GB Related terms: Full Clone, Template, Storage Efficiency, Thin Provisioning
Live Migration
Definition: Moving a running virtual machine from one host to another with zero downtime Real-world analogy: Like carefully moving a sleeping person from one bed to another without waking them Example: Moving a web server VM from Host A to Host B for maintenance without affecting website visitors Related terms: vMotion, Hot Migration, Zero Downtime
Lockdown Mode
Definition: A security feature that restricts direct access to ESXi hosts and forces management through vCenter Real-world analogy: Like a secure building where you can only enter through the main reception desk Example: Enabling strict lockdown mode so administrators must use vCenter instead of connecting directly to ESXi Related terms: Security, vCenter, Access Control, ESXi
M
Memory Overcommitment
Definition: Allocating more virtual memory to VMs than the physical host actually has Real-world analogy: Like a hotel booking more rooms than they have, counting on some no-shows Example: Allocating 100GB of virtual RAM across VMs on a host with only 64GB physical RAM Related terms: Memory Ballooning, Memory Compression, Resource Management
Micro-segmentation
Definition: Creating very granular network security policies, often down to individual VM or application level Real-world analogy: Like having individual security guards for each apartment instead of just one guard for the whole building Example: Web servers can only talk to app servers on port 8080, app servers only to database on port 3306 Related terms: NSX, Distributed Firewall, Network Security, Zero Trust
N
NFS (Network File System)
Definition: A network protocol that allows sharing storage over a network for use as VM datastores Real-world analogy: Like a shared storage unit that multiple people can access with their own keys Example: A NAS device providing NFS storage that multiple ESXi hosts can access for VM files Related terms: Datastore, Storage, VMFS, Shared Storage
NSX
Definition: VMware's network virtualization platform that creates virtual networks independent of physical hardware Real-world analogy: Like creating flexible room layouts using movable walls instead of permanent construction Example: Creating isolated networks for different departments using NSX without changing physical switches Related terms: Software-Defined Networking, Micro-segmentation, Virtual Networks
O
OVF (Open Virtualization Format)
Definition: An open standard for packaging and distributing virtual machines Real-world analogy: Like a standardized shipping container that can be moved between different types of ships and trucks Example: Exporting a VM as an OVF file to move it from VMware to another virtualization platform Related terms: OVA, VM Export, Portability, Standards
Overcommitment
Definition: Allocating more virtual resources (CPU, memory) than physically available, counting on not all VMs using maximum resources simultaneously Real-world analogy: Like a gym selling more memberships than they have equipment, knowing not everyone comes at once Example: Allocating 24 vCPUs across VMs on a host with only 16 physical CPU cores Related terms: Resource Management, Consolidation Ratio, Performance
P
P2V (Physical to Virtual)
Definition: The process of converting a physical computer into a virtual machine Real-world analogy: Like taking everything from a physical office and recreating it exactly in a virtual office space Example: Using VMware vCenter Converter to migrate a physical Windows server to a VM Related terms: Migration, Virtualization, Conversion, Legacy Systems
Paravirtualization
Definition: A virtualization technique where the guest OS is modified to work more efficiently with the hypervisor Real-world analogy: Like tenants who cooperate with building management instead of demanding special treatment Example: Linux guests using paravirtualized drivers for better network and storage performance Related terms: Hardware Virtualization, Guest OS, Performance Optimization
Provisioning
Definition: The process of creating and configuring new virtual machines with required resources and settings Real-world analogy: Like setting up a new apartment with furniture, utilities, and services for a tenant Example: Automated provisioning creates a new web server VM with 4GB RAM, 60GB disk, and Ubuntu 22.04 Related terms: Deployment, Automation, Template, Resource Allocation
Q
Quiescing
Definition: Temporarily pausing VM operations to ensure data consistency during snapshots or backups Real-world analogy: Like asking everyone in an office to stop working for a moment while taking a group photo Example: VM quiescing ensures database transactions are completed before taking a snapshot Related terms: Snapshot, Backup, Data Consistency, VSS
R
Resource Pool
Definition: A logical container for managing and allocating CPU and memory resources among groups of VMs Real-world analogy: Like designated parking areas for different types of vehicles (visitor parking, employee parking, executive parking) Example: Creating separate resource pools for Production (60% of resources), Development (30%), and Testing (10%) Related terms: DRS, Resource Management, Shares, Reservations, Limits
Resource Reservation
Definition: Guaranteeing a minimum amount of CPU or memory to a VM or resource pool Real-world analogy: Like reserving specific seats in a theater - they're guaranteed to be available Example: Database server VM with 4GB memory reservation ensures it always has at least 4GB available Related terms: Resource Pool, Limits, Shares, Performance
Resource Shares
Definition: A relative priority system for allocating resources when there's contention Real-world analogy: Like different classes of airline tickets - business class gets priority over economy Example: Production VMs with "High" shares get more CPU during busy periods than development VMs with "Low" shares Related terms: Resource Pool, Reservation, Limits, Priority
RTO (Recovery Time Objective)
Definition: The maximum acceptable time to restore service after a disaster Real-world analogy: Like the maximum time a restaurant can be closed before losing too many customers Example: Email system must be restored within 4 hours of a disaster (RTO = 4 hours) Related terms: RPO, Disaster Recovery, SLA, Business Continuity
RPO (Recovery Point Objective)
Definition: The maximum acceptable amount of data loss during a disaster Real-world analogy: Like the maximum number of transactions a bank can afford to lose Example: Customer database can lose at most 1 hour of transactions (RPO = 1 hour) Related terms: RTO, Disaster Recovery, Backup, Data Loss
S
Shared Storage
Definition: Storage that can be accessed by multiple ESXi hosts simultaneously Real-world analogy: Like a shared library where multiple schools can access the same books Example: A SAN providing shared storage so VMs can run on any host in the cluster Related terms: SAN, NAS, Cluster, vMotion, HA
Snapshot
Definition: A point-in-time copy of a VM's state, including memory, settings, and disk contents Real-world analogy: Like a save point in a video game that you can return to if something goes wrong Example: Taking a snapshot before installing software updates, allowing rollback if problems occur Related terms: Quiescing, Rollback, Backup, Point-in-time
Storage vMotion
Definition: Moving VM files from one datastore to another while the VM continues running Real-world analogy: Like moving all your belongings to a new storage unit without stopping your daily activities Example: Moving VMs from old slow storage to new fast SSD storage without downtime Related terms: vMotion, Storage Migration, Datastore, Zero Downtime
Storage Overcommitment
Definition: Allocating more virtual disk space than physically available using thin provisioning Real-world analogy: Like a bank lending more money than they have in deposits, counting on not everyone withdrawing at once Example: Creating 1TB of virtual disks on 500GB physical storage, expecting VMs won't use full allocation immediately Related terms: Thin Provisioning, Thick Provisioning, Storage Management
T
Template
Definition: A master copy of a VM used to create new VMs quickly with standardized configurations Real-world analogy: Like a cookie cutter that creates identical cookies from dough Example: Windows Server 2019 template with all patches and standard software for deploying new servers Related terms: Clone, Provisioning, Standardization, Deployment
Thick Provisioning
Definition: Allocating all requested virtual disk space immediately on physical storage Real-world analogy: Like renting an entire warehouse space even if you only use half of it initially Example: Creating a 100GB thick-provisioned disk immediately uses 100GB on the datastore Related terms: Thin Provisioning, Storage Allocation, Performance, Space Efficiency
Thin Provisioning
Definition: Allocating virtual disk space on-demand as the VM actually uses it Real-world analogy: Like paying for warehouse space only as you fill it with inventory Example: A 100GB thin-provisioned disk might only use 20GB of actual storage initially Related terms: Thick Provisioning, Storage Efficiency, Overcommitment
Type 1 Hypervisor
Definition: A hypervisor that runs directly on physical hardware (bare metal) Real-world analogy: Like a building superintendent who lives in the building foundation and manages everything directly Example: VMware ESXi, Microsoft Hyper-V Server, Citrix XenServer Related terms: Bare Metal, ESXi, Enterprise Virtualization, Production
Type 2 Hypervisor
Definition: A hypervisor that runs on top of an existing operating system Real-world analogy: Like a property management company that operates from a separate office building Example: VMware Workstation running on Windows 10, VirtualBox on Ubuntu Related terms: Hosted Hypervisor, Desktop Virtualization, Development, Testing
V
V2V (Virtual to Virtual)
Definition: Converting a virtual machine from one virtualization platform to another Real-world analogy: Like moving from one apartment building to another - same contents, different building Example: Converting a Hyper-V VM to run on VMware vSphere Related terms: Migration, Conversion, Platform Migration, Portability
vCenter Server
Definition: VMware's centralized management platform for multiple ESXi hosts and virtual machines Real-world analogy: Like a central command center that monitors and controls multiple buildings Example: vCenter managing 20 ESXi hosts and 200 VMs from a single web interface Related terms: ESXi, Management, vSphere, Cluster
Virtual Appliance
Definition: A pre-built virtual machine with an operating system and application already configured Real-world analogy: Like buying a fully furnished apartment instead of an empty one Example: A firewall virtual appliance that comes with the firewall software pre-installed and configured Related terms: OVA, OVF, Pre-configured, Deployment
Virtual CPU (vCPU)
Definition: A virtualized processor core assigned to a virtual machine Real-world analogy: Like assigning a portion of a chef's time to prepare meals for specific customers Example: A VM with 4 vCPUs gets processing time equivalent to 4 physical CPU cores Related terms: Physical CPU, Resource Allocation, Performance, Overcommitment
Virtual Disk
Definition: A file that acts as a hard drive for a virtual machine Real-world analogy: Like a digital filing cabinet that stores all of someone's documents Example: A 60GB VMDK file containing the operating system and applications for a web server VM Related terms: VMDK, Storage, Datastore, Thin/Thick Provisioning
Virtual Machine (VM)
Definition: A software-based computer that runs inside a physical computer Real-world analogy: Like an apartment in a building - it has everything needed to live but shares the building's infrastructure Example: A Windows Server 2019 VM running on an ESXi host with 4GB RAM and 60GB disk Related terms: Guest OS, Virtualization, Hypervisor, vCPU
Virtual Machine Monitor (VMM)
Definition: Another term for hypervisor - the software that manages virtual machines Real-world analogy: Like a theater manager who coordinates all the performances and manages the venue Example: The VMM allocates memory, CPU, and storage resources to each running VM Related terms: Hypervisor, ESXi, Management Layer
Virtual Network
Definition: A software-based network that connects virtual machines Real-world analogy: Like an internal phone system in a large office building Example: A virtual network allowing VMs to communicate without using physical network cables Related terms: Virtual Switch, VLAN, NSX, Network Virtualization
Virtual Switch
Definition: A software-based network switch that connects virtual machines to each other and external networks Real-world analogy: Like a telephone switchboard operator connecting different calls Example: A virtual switch with 4 port groups connecting VMs to different network segments Related terms: Port Group, VLAN, Network Virtualization, vSwitch
vMotion
Definition: VMware technology for moving running VMs between hosts with zero downtime Real-world analogy: Like carefully moving a sleeping person from one bed to another without waking them Example: Moving a busy web server from Host A to Host B for maintenance without affecting users Related terms: Live Migration, Zero Downtime, Shared Storage, EVC
VM Sprawl
Definition: The uncontrolled proliferation of virtual machines, often creating management and security challenges Real-world analogy: Like having too many storage units scattered around the city with no record of what's in each Example: IT team loses track of 50 test VMs that continue running and consuming resources unnecessarily Related terms: VM Lifecycle Management, Governance, Resource Waste
VMDK (Virtual Machine Disk)
Definition: VMware's file format for virtual hard disks Real-world analogy: Like a digital storage container that holds all of someone's files and programs Example: WebServer01.vmdk file containing the 60GB virtual hard drive for a web server VM Related terms: Virtual Disk, Datastore, Storage, File Format
VMFS (Virtual Machine File System)
Definition: VMware's clustered file system designed specifically for storing virtual machine files Real-world analogy: Like a specialized filing system designed for storing apartment blueprints and records Example: A 2TB VMFS datastore storing virtual machine files across multiple ESXi hosts Related terms: Datastore, Shared Storage, Cluster, File System
VMware Tools
Definition: A suite of software that improves VM performance and enables advanced features Real-world analogy: Like smart home features that help an apartment work better with the building's systems Example: VMware Tools enabling copy/paste between host and guest, automatic time sync, and optimized graphics Related terms: Guest Additions, Integration, Performance, Features
vSphere
Definition: VMware's virtualization platform including ESXi hypervisor and vCenter management Real-world analogy: Like a complete apartment building management system including the building and management office Example: vSphere environment with 5 ESXi hosts managed by vCenter Server Related terms: ESXi, vCenter, Virtualization Platform, VMware
W
Workload
Definition: The combination of applications, data, and computing requirements that run on a system Real-world analogy: Like all the activities and responsibilities of a particular job or department Example: A database workload requiring high memory and fast storage, or a web workload needing good network performance Related terms: Application, Performance Requirements, Resource Usage
Z
Zero Downtime
Definition: Maintaining service availability during maintenance or changes without any interruption Real-world analogy: Like changing a tire on a moving car - the service never stops Example: Using vMotion to move VMs off a host for maintenance without affecting running applications Related terms: vMotion, HA, Live Migration, Business Continuity
Common Acronyms Quick Reference
| Acronym | Full Name | Simple Definition |
|---|---|---|
| DRS | Distributed Resource Scheduler | Automatically balances VM workloads |
| ESXi | Elastic Sky X Integrated | VMware's bare-metal hypervisor |
| HA | High Availability | Automatic VM restart on host failure |
| IaaS | Infrastructure as a Service | Cloud-based virtual infrastructure |
| NFS | Network File System | Network storage protocol |
| NSX | Network Service eXtension | VMware's network virtualization |
| OVA | Open Virtual Appliance | Single-file VM package |
| OVF | Open Virtualization Format | VM packaging standard |
| P2V | Physical to Virtual | Converting physical to virtual machine |
| RPO | Recovery Point Objective | Maximum acceptable data loss |
| RTO | Recovery Time Objective | Maximum acceptable downtime |
| SAN | Storage Area Network | Dedicated storage network |
| VADP | vSphere APIs for Data Protection | VM backup interfaces |
| VDI | Virtual Desktop Infrastructure | Centralized desktop virtualization |
| VM | Virtual Machine | Software-based computer |
| VMDK | Virtual Machine Disk | VMware virtual disk format |
| VMFS | Virtual Machine File System | VMware's cluster file system |
| VMM | Virtual Machine Monitor | Another term for hypervisor |
| vSAN | Virtual Storage Area Network | VMware's software-defined storage |
| V2V | Virtual to Virtual | Converting between virtualization platforms |
Study Tips for Vocabulary
Memory Techniques
- Use the analogies: The real-world comparisons help connect technical concepts to familiar experiences
- Group related terms: Study hypervisor types together, storage terms together, etc.
- Practice with scenarios: Use the terms in context - "The DRS feature uses vMotion to balance workloads"
- Create concept maps: Draw connections between related terms to show relationships
Common Confusions to Avoid
- Type 1 vs Type 2 Hypervisor: Type 1 runs on bare metal (enterprise), Type 2 runs on OS (desktop)
- Clone vs Template: Clone is a copy you can modify; template is a master for creating new VMs
- Thick vs Thin Provisioning: Thick allocates all space immediately; thin allocates as needed
- vMotion vs Storage vMotion: vMotion moves running VMs; Storage vMotion moves VM files
- HA vs FT: HA restarts VMs after failure; FT prevents downtime during failure
- Snapshot vs Backup: Snapshots are temporary and affect performance; backups are for long-term protection
Vocabulary in Context Examples
Scenario-based learning:
- "We need to implement HA in our cluster so VMs automatically restart on surviving hosts when hardware fails"
- "The DRS feature will use vMotion to balance workloads across ESXi hosts in the cluster"
- "Our backup strategy uses snapshots for point-in-time recovery and templates for rapid provisioning"
Practice Activities
- Definition matching: Match terms with definitions without looking at answers
- Scenario identification: Read virtualization problems and identify which terms apply
- Explain to others: Try teaching these concepts using the analogies provided
- Real-world application: Identify how these terms apply in your current or target work environment
Professional Usage
In job interviews: "I have experience with vSphere environments including ESXi host management, VM provisioning, and DRS configuration"
In documentation: "Implemented HA cluster with shared storage to provide zero downtime during maintenance using vMotion technology"
In troubleshooting: "Checked resource utilization, examined VMware Tools status, and reviewed snapshot chain for performance issues"
This vocabulary foundation will help you communicate effectively about virtualization concepts and technologies in professional environments.