Re: [PATCH v3] doc: Define a standard URI syntax for NBD URIs.
On Tue, Jun 11, 2019 at 02:51:47PM +0100, Richard W.M. Jones wrote:
> On Tue, Jun 11, 2019 at 03:29:03PM +0200, Wouter Verhelst wrote:
> > Hi Richard,
> >
> > LGTM, for the most part. One minor detail: should we document that the
> > URLs should only be used for newstyle connections? I don't honestly
> > think that using oldstyle is a good idea anymore, so we might as well
> > drop it and assume that people don't want to try oldstyle anymore, but
> > then...
>
> We support it in libnbd and nbdkit!
>
> Longer more serious answer: I don't think we should stop people using
> oldstyle even though I agree that newstyle is the superior choice in
> every respect.
I agree with that.
However, oldstyle and newstyle are not compatible[1]; so it may be
necessary for the URI to specify whether the connection should use
oldstyle or newstyle.
My first suggestion was going to be that we add a parameter to specify
oldstyle (the default should be newstyle); but then I was thinking that
not many servers would implement oldstyle anymore. Hence that
suggestion.
> One actual reason to still be using oldstyle is
> because you've got some old server which you can't / don't want to
> update. I have encountered a few of these in niche places (VMware is
> one, and just about any hit for "NBD" on github that was started
> before 2010 will be using oldstyle).
Sure.
We can still add a "?oldstyle" parameter to specify oldstyle, or some
such. I just don't know whether it's worth it.
[1] theoretically it should be possible to detect the oldstyle magic
number and fall back to oldstyle if supported, but that's a bit ugly
and I don't want to write that in stone for clients/libraries that
support it. It makes sense to require that oldstyle/newstyle is
explicitly selected in the URI instead.
--
<Lo-lan-do> Home is where you have to wash the dishes.
-- #debian-devel, Freenode, 2004-09-22
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