VMware ESXi and vSphere Cluster Management

Edit Virtual Machine Settings in VMware ESXi and vSphere

Learn how to open Edit Settings in vSphere and safely change VM CPU, memory, disks, networking, devices, and VM options.

The vSphere Edit Settings dialog is used to view and change an existing virtual machine's virtual hardware and management behavior. You might edit a VM to meet increased CPU or memory demand, add a network connection, provide more storage, attach a device, or adjust operational settings.

These are configuration changes to the virtual machine platform. They are not the same as changes inside the guest operating system, which is the operating system installed in the VM. For example, adding a virtual hard disk in vSphere does not automatically create a partition or filesystem in Windows or Linux.

What the Edit Settings Dialog Contains

The dialog is organized mainly into Virtual Hardware and VM Options.

Dialog area — Settings represented — Typical use case — Validation after change

Virtual Hardware — vCPUs, memory, virtual hard disks, controllers, network adapters, USB devices, CD/DVD devices, and other supported devices — Increase resources, add storage, connect a VM to another network, or attach a device — Confirm the vSphere task completes, then verify the device or resource in the guest OS.

VM Options — Behavioral and management features such as guest time synchronization and VMware Tools update-check behavior — Align VM behavior with operational standards — Check time behavior, VMware Tools status, and any application effect.

Available controls depend on the vSphere release, VM compatibility level, current power state, guest support, permissions, host and cluster policy, and available resources. Menu names can therefore differ slightly between environments.

Open Edit Settings in the vSphere Client

  1. Sign in to the vSphere Client with an account that has permission to edit the VM.
  2. Locate the target virtual machine in the inventory.
  3. Open the VM's context menu.
  4. Choose Edit Settings.
  5. Use Virtual Hardware for hardware changes or VM Options for behavior and management settings.

If the option is unavailable, check permissions, the VM power state, compatibility, and host or cluster restrictions. An administrator may need to use an approved maintenance process or change the VM's compatibility level before the required control is available.

Plan the Change Before Editing

Before opening the dialog, write down the requested target state and determine what the guest and applications will experience. Increasing memory may require guest recognition or a reboot. Adding a NIC may require a new IP address, route, DNS configuration, firewall rule, or application binding. Adding a disk may require partitioning and filesystem work.

  • Review the current VM configuration and recent CPU, memory, storage, and network usage.
  • Confirm host capacity, resource allocation policies, datastore free space, storage visibility, and network availability.
  • Determine whether the VM must be powered off. Do not assume that a powered-on change is safe merely because the dialog permits it.
  • Confirm guest OS, application, licensing, driver, and online-expansion support.
  • Check that backups and recovery procedures are current and appropriate for the risk.
  • Record the approved change, expected downtime, previous values, target values, and required guest-side work.

A snapshot can be useful for specific short-term operational tasks, but it is not a substitute for a tested backup and recovery plan.

Power State, Hot Add, and Hot Plug

Hot add or hot plug means adding or expanding a supported resource or device while the VM remains powered on. Support depends on the vSphere version, VM compatibility, VM configuration, guest OS, device type, and enabled capabilities. Many changes, especially reductions or topology changes, require a shutdown.

Setting or device — Typical change — May be possible while powered on — Dependencies or cautions — Guest-side follow-up

vCPU — Increase CPU count — Sometimes, with CPU hot add and guest support — Licensing, host capacity, topology, and application scheduling matter — Confirm processor count and application behavior.

Memory — Increase assigned RAM — Sometimes, with memory hot add and guest support — Guest limits and NUMA or performance effects may apply — Confirm available memory and restart if required.

Virtual hard disk — Add capacity or a new disk — Often possible for supported configurations — Adding capacity does not extend a guest partition or filesystem — Rescan, initialize, partition, format, mount, or extend as appropriate.

Ethernet adapter — Add another virtual NIC — Often possible — Port group, VLAN, security, routing, and guest configuration must be correct — Detect the NIC and configure its address and routes.

USB controller — Add a virtual USB controller — May be possible — Device and host compatibility are required — Install or verify drivers and confirm device ownership.

SATA controller — Add a controller — May be possible — Compatibility and powered-on restrictions vary — Rescan devices and verify controller drivers.

RDM — Present a mapped physical device or LUN — Depends heavily on configuration — Storage visibility, host setup, compatibility, and workload requirements apply — Rescan and verify the intended device identity.

Time synchronization option — Change guest and host time behavior — Usually a VM option change — Avoid conflicting time sources, especially for domain or distributed systems — Check guest time source and drift.

VMware Tools update-check option — Change Tools update-check behavior — Usually a VM option change — Available controls vary by release and compatibility — Verify VMware Tools status and organizational policy.

After every online change, inspect the vSphere task result and verify that the guest OS detected the change. A successful vSphere task does not guarantee that the guest can use the new resource.

Change Virtual CPU and Memory

In Virtual Hardware, change the number of vCPUs or the assigned memory. A vCPU is a virtual processor scheduled on physical host CPU resources. More configured resources are not automatically better: host contention, cluster policy, resource reservations or limits, application design, and guest OS licensing can affect the result.

When CPU topology controls are available, consider cores per socket as well as the total vCPU count. Topology can affect guest licensing, NUMA behavior, and application interpretation. Use the topology recommended for the workload rather than changing it casually.

CPU and memory hot add must be configured and supported before the VM is powered on for an online expansion. Decreasing CPU or memory, changing certain topology settings, or using an unsupported guest commonly requires a shutdown. After applying the change, verify the guest hardware inventory and application health.

Add or Remove Virtual Hardware

Use Add New Device in Virtual Hardware to add supported devices. Common categories include virtual disks, network adapters, controllers, USB devices, CD/DVD devices, and other platform devices. Configure storage placement, controller attachment, port group, connection state, or other device-specific values before saving.

Removing a device is more dangerous than adding one. A disk may contain an operating system, database, swap area, boot files, or application data. A NIC may be required for management or application traffic. Identify the device using stable information such as capacity, controller location, MAC address, and guest mapping. Confirm backup and recovery implications, stop dependent services when required, and remove only after the dependency is understood.

Add Storage: Virtual Disks and RDM

Virtual hard disk

  1. Open Edit Settings and select Virtual Hardware.
  2. Choose Add New Device and select a virtual hard disk.
  3. Specify the size, storage placement, provisioning behavior available in the environment, and controller assignment.
  4. Review datastore capacity and storage policy before applying the change.
  5. After vSphere reports completion, rescan storage in the guest OS.

Adding a virtual disk increases the device presented to the VM; it does not automatically extend a guest partition or filesystem. The guest administrator may need to initialize the disk, create a partition, format it, mount it, or extend an existing filesystem.

Raw Device Mapping

RDM, or Raw Device Mapping, presents a physical storage device or LUN to a VM through a mapping. It may be required by a particular workload or storage design, but it is not a general replacement for a virtual disk. RDM selection depends on storage visibility, host configuration, compatibility, and workload requirements. Confirm the intended LUN identity and recovery procedure before attaching, changing, or removing an RDM. For a related storage procedure, see Add a Raw LUN.

Change Virtual Networking

To add a second network connection, add a virtual network adapter under Virtual Hardware and select the correct port group. A port group is the virtual networking configuration that connects the adapter to an ESXi virtual switch and its associated network behavior.

  • Confirm the selected port group and VLAN design.
  • Verify upstream routing, firewall, security policy, and network availability.
  • Apply the change and confirm the adapter's connection state.
  • Identify the new interface in the guest using its MAC address.
  • Configure IP addressing, routes, DNS, firewall rules, and application bindings in the guest.
  • Test interface status, local gateway access, DNS resolution, and required application connectivity.

Do not identify a NIC only by its position in a list. MAC address and guest-side interface mapping are safer identifiers, especially when several adapters are present.

Configure VM Options

VM Options contains behavioral and management settings, not only hardware. Review guest and host time synchronization carefully. A guest can receive time from the host, its own time service, or another configured source; conflicting time sources can cause drift or repeated corrections.

VM Options may also include VMware Tools update-check behavior. VMware Tools is guest-side software that improves device support, integration, and management. Apply update-check and synchronization settings only when they match the organization's operational requirements. Other options vary by vSphere release and VM compatibility, so do not change an unfamiliar setting without understanding its effect.

Save, Apply, and Validate

  1. Review every changed value, device, storage location, controller, port group, and option.
  2. Confirm that removal actions are intentional.
  3. Select the dialog's save or apply control.
  4. Monitor the vSphere task or Recent Tasks area until it completes or reports failure.
  5. Power on or reboot the VM when the change requires it.
  6. Perform guest OS and application validation.
  7. Record the final configuration and any remaining guest-side work.

Change type — vSphere validation — Guest OS validation — Application or network validation

CPU or memory — Task completed and target values shown — Processor and memory inventory reflects the change — Application performance, licensing, and service health are normal.

Network adapter — Adapter is connected to the intended port group and has the expected MAC — Interface is present, enabled, and correctly addressed — Test routes, DNS, firewall behavior, and required connections.

Virtual disk — Disk size, datastore, controller, and attachment are correct — Disk is detected and correctly initialized or mounted — Confirm expected capacity, permissions, and application access.

Controller or USB device — Device and compatibility status are correct — Driver and device inventory are correct — Confirm the dependent application can use the device.

VM Options — Selected options are saved — Time and VMware Tools behavior match expectations — Check time drift, Tools status, and service behavior.

Practical Examples

Increase resources for a busy application VM

  1. Review CPU and memory utilization and establish approved target values.
  2. Determine whether CPU hot add or memory hot add is enabled, supported, and accepted by the guest OS.
  3. If not supported, schedule a shutdown.
  4. Change vCPU and memory in Virtual Hardware.
  5. Monitor the task, start or reboot the VM as needed, and verify resources in the guest and application.

Add a second network connection

  1. Add an Ethernet adapter under Virtual Hardware.
  2. Select the correct port group and confirm connection settings.
  3. Apply the change and identify the NIC in the guest by MAC address.
  4. Configure the interface, address, routes, DNS, and firewall rules.
  5. Verify gateway access, DNS, and application connectivity.

Add storage to a VM

  1. Choose a virtual hard disk or, where specifically required, configure an RDM.
  2. Confirm datastore or LUN availability and controller assignment.
  3. Apply the change and verify the vSphere task.
  4. Rescan storage in the guest.
  5. Initialize, partition, format, mount, or extend the filesystem according to the guest OS procedure.

Adjust management behavior

  1. Open VM Options.
  2. Review time synchronization and VMware Tools update-check settings.
  3. Apply only settings supported by organizational policy.
  4. Validate guest time, time source, and VMware Tools status.

Troubleshooting Edit Settings Changes

Edit Settings is unavailable or a setting cannot be changed

Likely causes include insufficient vSphere privileges, a powered-on VM that does not support the requested hot-plug operation, an incompatible VM hardware level or vSphere release, or host, cluster, storage, or policy constraints. Verify the assigned role and scope, check the required power state and compatibility, and use an approved maintenance window if shutdown is necessary. See Assign Permissions for role-related administration.

A new network adapter has no connectivity

Confirm the adapter is connected to the intended port group. Then verify VLAN and upstream network configuration, guest interface detection, IP addressing, routes, DNS, firewall rules, and application bindings. A successful vSphere task alone does not prove network connectivity.

A new disk is visible in vSphere but unusable in the guest

The guest may need a storage rescan, or the disk may be uninitialized and lack a partition or filesystem. Confirm disk identity and capacity, check controller and driver support, and complete the guest OS storage procedure. Also verify that the intended disk, rather than another device, was attached.

CPU or memory changes do not appear in the guest

Check the vSphere task result, hot-add configuration, guest support, and whether a reboot is required. If the online operation was unsupported or incomplete, restart during an approved maintenance window and recheck the guest hardware inventory.

Removing a device caused an outage

The device may have been in use, incorrectly identified, or removed before guest configuration was updated. Restore service through the approved recovery process, then identify devices by stable identifiers and coordinate future removals with application owners.

Operational Constraints and Exam Notes

  • Editing permissions are controlled by vSphere roles and privileges; inventory visibility does not necessarily grant configuration rights.
  • Host CPU and memory, datastore space, storage visibility, device compatibility, cluster policy, and VM configuration can restrict a change.
  • Hot add or hot plug is conditional, not universal. Always check the task result and guest detection after an online operation.
  • Adding virtual storage is separate from extending a guest partition or filesystem.
  • Removing a virtual device can disconnect it or permanently remove access to data; identify its guest purpose first.
  • Increasing resources does not bypass guest OS limits, licensing, application limits, or host contention.
  • Snapshots are not tested backups.

For broader administration practice, see the VMware ESXi Online Course, Configure vSphere Networking and Port Groups, or Clone a Virtual Machine.