Skip disk size requests for ISO files when retrieving VMs

When retrieving VMs, you can configure the platform to skip the request for the disk size of an ISO disk, to improve speed and reliability. This is especially useful if many VMs in your platform use ISO disks.

By default the platform will try to obtain the size of all disk files, which depends on the full availability and speed of the datastores.

To skip the request for disk size and set disk size to 0 for ISO disks on retrieved VMs, set this property on the Remote Services servers.

Notes

This configuration has the following limitations:

• When capturing a VM that uses an ISO, the platform will report 0 size for the discovered ISO disk.

• When adding an ISO to an existing VM, the platform will discover the ISO disk and report 0 size. This includes Cloud-init ISOs, which usually have a small size.

• The platform will not include the capacity of discovered ISO disks when it checks limits and quotas, so users may obtain bonus storage space for these disks.

The platform manages pass through devices (without file backing) as size 0 disks but it does not record a datastore for them.

The platform updates datastore usage with a separate check, so the platform will correctly allocate datastore space.

Use cases

When you enable this configuration, the platform will not change the size of ISO disks already in VMs to 0.

When the configuration is enabled:

• If you retrieve VMs, the platform will skip the request to obtain the disk size and set disk size to 0 for ISO disks

• If you deploy a VM with a template that includes an ISO disk (e.g. ubuntu-install.iso), the ISO disk in the VM will have the size from the VM template

• If you deploy a VM using cloud-init or add an ISO that is disk backed, the platform discovers the ISO disk, sets size=0, and reports the datastore

After you disable this configuration, the platform will update the size of existing ISO disks in VMs to their correct size.