Some comments on using qemu-storage-daemon

[Richard W.M. Jones]

I understand that QSD is at an early stage of development and I'm sure
you have plans to fix these things.  Nevertheless here are my comments
after trying to add an interop test with libnbd.

(1) Documentation!  (Or complete lack of it ...)  I had to ask Kevin
how to construct the command line because several things were not
obvious.  In particular the --blockdev parameters only make sense if
you're already used to constructing blockdev parameters (and these
are, separately, not well-documented).  And you have to supply the
parameters in a particular order on the command line, else it doesn't
work.

(2) There seems to be no --pid-file option, so there's no way of
knowing when the server is ready to accept connections, except to
start QSD and then "sleep for a bit".

(3) Seems to be no support for either serving requests over
stdin/stdout (qemu-nbd also lacks this, but it's common for other NBD
servers); or for systemd socket activation (qemu-nbd supports this).

(4) Some parameter names changed between 5.1 and upstream.  I
understand that you're still finalizing the command line, so this
isn't a problem in itself, but others who try to use QSD will need to
be aware of it.

Rich.

-- 
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