I had in mind (still do) to use Cinnamon as a host for virtual machine. In fact, I have had that idea in the back of my mind for many years. Recently that idea percolated up to the top again, and one thing I did was to buy some additional ram for it, I bought a 16G stick and tried to add it. It wouldn’t boot. The very poorly written manual on the motherboard seems to suggest that it absolutely requires one to have balanced sticks in the dimm slots. I find that hard to believe, but decided it couldn’t hurt to comply, and bought another stick, so I would have 2 8G sticks, and 2 16G sticks, 48G.

It still wouldn’t boot. But I noticed that this doesn’t look like the hardware is failing – it gets up into Xen and then stops. I don’t think this is a hardware problem with the memory.

After some googling around I found an article on the Suse website with a similar thing, saying that Dom0 won’t come up if it has more than 32G of memory, and offering a solution.

I’m very ignorant about Xen. I have never really gotten beyond installing it, with my Cinnamon ubuntu installation in Dom0 and using all the resources. But, but it is clear of course that the right way to do this is for the Dom 0 to be small and confined to its management job, and Cinnamon should actually be a Dom U.

What seems to be true is that if you do not specify on the command line, the Dom 0 will come up with all the memory. And that if you have more than 32GB of memory for it to come up with it will fail. Thus if you have more than 32GB of memory, you MUST avail yourself of the command line to limit the memory available to Dom 0.

I added to the linux command line in the default grub,:

dom0_mem=8G

And the box came up fine. Once I manage to get Cinnamon and it’s functions into separate Dom U, I will reduce the dom0 down to 1 G or so.