On Fri, Mar 27, 2015 at 01:27:39PM -0600, Eric Blake wrote:
Is NBD bi-directional, in that the target can receive write requests
at
the same time it is sending read requests?
It's unidirectional. It's a very simple protocol - you can't even
answer requests out of order:
https://github.com/yoe/nbd/blob/master/doc/proto.txt
In an ideal world for libguestfs we'd have qemu be the NBD server,
with some sort of monitor command like:
drive-point-in-time-snapshot device:virtio-disk1 port:1000 id:123
then you'd connect to <qemu-server>:1000 and it'd give you access to
the drive at that instant in time until there was a further command to
discard the snapshot:
drive-discard-point-in-time-snapshot id:123
Rich.
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