OVH Guides

Modifying virtual machine resources

Find out how to scale your virtual machine

Last updated 25th June 2020

Objective

Once you have created your virtual machine (VM), its resources are not permanently set. They can be reallocated to make your infrastructure more agile, with some restrictions.

This guide will explain how to scale your virtual machine.

Requirements

Instructions

All the modifications described below must be made from your Private Cloud on vSphere by right-clicking on a VM, then on Edit Settings.

Editing resources

In this menu, you can increase your virtual machine’s resources.

Editing resources

For more information on the option to add devices, please refer to the section below.

The processor (CPU)

The number of CPUs will be limited to the slots available on the host.

If your virtual machine migrates to a host with fewer processors than those allocated to your machine, the "CPU ready" status of the VM will rise, which will result in performance loss.

Add a CPU

You can also set a specific frequency (minimum and maximum) and choose the number of cores per socket.

If you tick the Enable CPU Hot Add box, you can modify these values while the virtual machine is running.

Depending on the operating system you are using, hot adding may not work, and could cause a malfunction on the host.

You can assign a minimum number of MHz to your virtual machine.

The limit, which is unlimited by default, allows you to restrict your virtual machine’s processor to a value in MHz. You can, for example, limit a developer virtual machine.

Memory (RAM)

As with the CPU, the RAM capacity is limited to the host’s resources.

You can assign RAM so that your virtual machine always has a minimum amount of RAM reserved.

Add memory

The hard disk

You can increase the hard disk size according to the space left in the datastore used by the virtual machine.

Add storage

We recommend that you use SCSI disk controllers rather than IDE ones, as you cannot, for example, perform backups via Veeam with IDE controllers.

You can also select the disk mode:

  • Dependent: includes the disk during snapshots

  • Independent - persistent: allows you to store data when you reboot a machine, but this is not taken into account during a snapshot

  • Independent - non-persistent: is unique in that it does not save data: if you reboot the machine, all the data will be deleted.

The network adapter

You can modify your virtual machine’s network adapter, the connection to the adapter when starting up the virtual machine, and the adapter type. You can also verify the port ID and your MAC address.

Add network

This interface is useful in the event of a network malfunction. You can verify that the port ID corresponds to the ID listed in the Networking and Ports tabs for that adapter.

The CD/DVD drive

A virtual CD/DVD drive allows you, for example, to mount ISO images on your virtual machine.

Add a CD/DVD reader

We recommend that you delete the CD/DVD drive after using it, as it could in fact prevent the virtual machine from being moved.

Adding a device

At the bottom of this window, you can add additional devices.

You can add disks from another datastore, or network adapters, if you need to use several private networks.

Add devices

Go further

Join our community of users on https://community.ovh.com/en/.


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