Having spent a while searching for answers on this I am making a last-ditch effort by contacting the devel group.
Could someone let me know if it is possible to change the default disk cache setting in qemu globally?
Currently it is set to writeback, in many if not most use cases "none" is optimal.
I am aware I can change it per instance however I really need to find a global method so that unless specified otherwise the default becomes cache=none
It does seem a little strange that options appear to exist:
qemu-img -h | grep writeback
options are: 'none', 'writeback' (default, except for convert), 'writethrough',
However I can't find any documentation that hints at a method of changing the default, rather all documentation provides is a method per use/instance.
Appreciate any assistance even if the answer is just "Not possible" so I can at least drop this search for answers.