When I push out new releases of dtrace, I cannot apply as high
a level of quality as I would like. I had set myself up a nice
environment to cross-compile from a single system, against lots of
kernels, but for various reasons, that didnt work.
I have a nice collection of VMs for lots of versions of Linux - going
back to very old versions. Originally, under VMWare, but over the last few
years, VirtualBox. I like VirtualBox, but I also have problems with it.
VMware (vmplayer) is nice, but very limited. I did get bored of
vmware not being installable in new kernels, and requiring hacky
patches to the source code to make it work.
But I am somewhat annoyed that many of my VMs seem to have "broken" or
"gone off". E.g. Centos 4.7, 5.5, 5.6 -- they no longer boot under
VirtualBox. I have tried various things - they used to work, but
no longer do. So, my supply of VMs is limited. (Each VM has my
set of customisations, to make them comfortable to login to). Its
a nuisance having to reset them up, or try and guess why an old
kernel no longer works.
I may have to go back to vmware or try out kvm, to see which works
best for me.
This really is a big problem - may not recognised by the industry - but
a VM which stops being usable, due to a host upgrade or VM software
upgrade, really demeans the valuableness of having VMs in the first place.
It might be that I could downgrade my VirtualBox to restore the older
VMs, but this is turning into a job-creation scheme, rather than
a productivity boost.
I really dislike VirtualBox's nested-snapshot mechanism - despite its
power, its confusing -- very confusing and you can end up reverting
a snapshot and losing a lot of data. VMwares snapshot/restore was
much simpler to get along with.