Have a look at mkinitfs-bootparams(7)
These are options you can pass to the linux cmdline
. Specifically overlaytmpfs
and overlaytmpfsflags
may be of interest.
I don't use QubesOS (anymore) but I do use Xen and have a few domUs and I implemented overlaytmpfsflags
to be able to give domUs a read-only disk and as little memory as possible.
As an example, I have a domU in which I run Tor and dnscrypt-proxy, that I use like you would a QubesOS ProxyVM, and I give it 160MB of RAM (memory = "160"
), I pass a zvol as a read-only disk and give the overlaytmpfs
32MB to write to (default is half of available RAM, tmpfs(5)
) with overlaytmpfsflags=size=32m
.