Why VMWare does not support dynamic resource provisioning when the VM is running?

[gogator]

Hi,

As a user of VMWare software and a computer scientist, I am wondering why most of virtual machine hypervisors including VMWare do not support dynamic resource provisioning at run time. If I can change memory size, cpu core without restarting VM, it would be a cool feature. Does anyone explain why it is not supported? I suspect it is hard for operating systems to manage dynamically changing resource status. Technically-detailed explanation should be fine. Thanks in advance.

[BLjellis]

If it is supported by the guest OS you should be able to increase disk, CPU count and memory. This is also true in vCloud Director.

[NuggetGTR]

I believe VMware will support the adding of resources just not the removing of resources, but as mentioned i nthe above post its usually an OS limitation not a hyper-visor limitation.

you should be able to change the disk size or add extra HDD on the fly for most systems

Hot adding memory, windows 2003 ent and all 2008 editions edition can handle hot adding memory but you cant remove memory on the fly. (only condition to that is 2008 std editions requires a restart to pick up the added memory the rest should be fine without a restart)

and as far as I know only 2008 x64 editions can hot add CPU's but again cant remove them on the fly. (and the only condition to this is that all but the DC editions have to restart to pick up the added CPU's.)

Im sure support for the OS side will get better for hot plug and unplug support,

I also know there is some linux distros that can handle it but I dont play with linux as much

to do this tho you need to enable hot plug cpu and mem in the virtual machines options, and the machine has to be off to enable this first

[gogator]

Thank you very much for your nice answers. It helps me a lot.