Re: [Qemu-devel] [PATCH 0/2] Enable qemu block layer to not flush

[Jamie Lokier]

Stefan Hajnoczi wrote:
> Why add a nop AIO operation instead of setting
> BlockDriverState->enable_write_cache to zero?  In that case no write
> cache would be reported to the guest (just like cache=writethrough).

Hmm.  If the guest sees write cache absent, that prevents changing the
cache policy on the host later (from not flushing to flushing), which
you might want to do after an OS install has finished and booted up.

-- Jamie