Adding a different type of blockstore to Bhyve

[Paul Vixie]

On Monday, 30 December 2019 18:06:11 UTC Willem Jan Withagen wrote:
> Something like:
>    bhyve -s 1,virtio-blk,rbd:poolname/imagename[@snapshotname] \
>                           [:option1=value1[:option2=value2...]]

this is approximately how i'd hope to do object-store level ZFS integration, 
so as to avoid the zvol abstraction. i know you're working on Ceph not ZFS but 
the concepts and facilities are similar enough to warrant cooperative 
thinking.

> So the questions are:
> 1)   Is the abstraction of block_backends.{ch} the way to go?
> 1.1) And would the extra indirection there be acceptable?
>       (For network devices it seems no problem)
> 
> 2)   Does anybody already have such a framework for blockdevs?
>       (Otherwise I'll try to morph the net_backends.{ch}
> 
> 3)   Other suggestions I need to consider?

i think you're hitting an architectural limit, and that the bhyve design team 
should be thinking about a third way, one which would also solve my own 
loopback and mmap requirements as i've described variously. what you want to 
do should not only be possible, it should be clean and performant.

-- 
Paul