RANT: Unimpressed by VMs

[sphbecker]

So yeah, this will be somewhat of a rant, but I mean it in a constructive way, hoping for improvements and hoping others may know some under-the-covers ways to workaround these limitations.

 

I have worked with professional hypervisors for over a decade, so I understand virtualization very well. Over the years I have run ESXi, HyperV and KVM on my home server, never had a big issue with any of them, I just like like to try out new things. This time around I decided to give unRaid a try, figuring it would have most of the perks of KVM without all of the tinkering. At first glace, its pretty promising. If you just need to run a VM or two, its great.

 

However, I have run into a few seemingly odd limitations with unRaid's VM implementation that seem odd to me and could probably be easily addressed. Here are my complaints so far.

 

• Required core pinning. To me this is the worst limitation. Core pinning is for advanced tuning and shouldn't be needed in most uses cases, requiring it is bad. Just let us set the number of vCPU and have the hypervisor allocate as needed. If you only run a few VMs this isn't a huge issue, but it vastly limits scalability and creates the potential for bottlenecks on individual cores even if the system has availability on others.
• Host network settings are locked down unless you stop all VMs and Dockers. Not sure what the thinking was here, but that is an insane limitation for any modern system.
• All Guest VM settings are locked while running. Sure, some settings can't be changed while running, but many can on other platforms. The ability to add an additional disk or network card or change network connection without shutting down would be nice. Nearly every other platform supports that...even something as simple as Virtual Box.
• There seems to be only one virtual network bridge. Probably fine for most use cases, but if you wanted to setup a network lab to test multiple virtual routers, you don't have the ability to create a virtual network segment for each interconnect.

 

A few good things I can say about it.

• Setup process is surprisingly easy and covers all the needs of nearly all home server operators.
• Hands down the easiest system I have seen for directly assigning hardware to a VM.

[trurl]

Didn't seem like a rant except for the subject line