On Tue, Mar 20, 2018 at 11:57:46AM +0300, Vladimir Sementsov-Ogievskiy wrote:
19.03.2018 17:39, Eric Blake wrote:
Can you demonstrate an actual sequence of commands sent over the wire,
for how it would be useful?
- we initialize two drives A and B in qemu and setup copy-on-read for them.
- client send a sequence of READAHEAD commands, and data is copied from A to
B on read from B, in corresponding sequence.
So, here B is a cache in terms of the PRE-FETCH command.
This sounds very similar to what xNBD does
(https://bitbucket.org/hirofuchi/xnbd/wiki/Home). Can you confirm?
If so, I suppose it makes sense to add the current behaviour of xNBD to
the spec, rather than inventing our own thing.