Maximum VM capacity per host calculations (Novice User Warning)

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Horseman6670
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Joined: 16. Mar 2019, 17:38

Maximum VM capacity per host calculations (Novice User Warning)

Post by Horseman6670 »

I want to do calculations to estimate the maximum number of virtual machines I can realistically run simultaneously on the one host machine, under the assumption that they are all the same OS and have equal workload requirements, for a learning project about how multiple computer systems interface with one another.

The oracle website says a maximum of 32, but I'm confused by how this can be a multiplatform constant seeing it logically would depend on the processing power of the host machine, and the sum of the individual processing workload of each VM, or at least from a novice view this is what I expected.
mpack
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Re: Maximum VM capacity per host calculations (Novice User Warning)

Post by mpack »

Horseman6670 wrote: The oracle website says a maximum of 32, but I'm confused by how this can be a multiplatform constant
Naturally not - that's a maximum, not a minimum. And anyway it has nothing to do with resources, it's about what the VirtualBox infrastructure supports. Only you can know what resources are available on your host.

In practice you usually need to have one CPU core per VM, and enough RAM to give a useful amount for the exclusive use of the VM. And still have plenty CPU and RAM left over to run the host OS efficiently (an inefficiently running host can't run VirtualBox).

For most people, if the VMs are actually doing work and not just idling, then a couple of VMs is the practical limit. If the VMs are basically idling and occasionally waking up then you can only find the practical limit by experiment. It is VERY guest OS and application dependent.
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