Re: [Nbd] How does nbd handles broken link ?

[Wouter Verhelst <w@...112...>]

On Sun, Jan 21, 2007 at 08:39:44PM -0800, gary ng wrote:
> Hi,
> 
> I am wondering how nbd handle temperary broken links.
> 
> This could happen say because there is network error.
> Or the nbd server reboot.

Currently, it doesn't handle these errors, unless you use the "-persist"
option on the client side.

> In NFS, it is possible for it to wait until everything
> comes back.

Yes, and I do agree that it would be better if this were possible with
NBD, too; there are some plans in that direction, but they haven't
happened yet.

> Do I need to manually handle this kind of situation
> using NBD ?
> 
> Another unrelated question, is it possible for the
> client to use unix domain socket ? It may sound
> redundant as one may ask why not serve that
> file/device directly ?

Currently no. However, the code should be updated at some point to
support IPv6 sockets, too, and then doing Unix domain sockets too should
(theoretically) not be too hard. I'll keep it in mind.

> The answer is that I like NBD as a standard device
> node/module with linux and want to plug other backend
> store through it. So I just need to write a server
> speaking NBD which can then do its own data serving.

Yes; this is also what VMware used to do in their version 3 series,
IIRC (at least in the only version which I ever used :-).

> Currently, I can use 127.0.0.1 but is wondering if
> there is any advantage using domain socket.

Not sure about that, although I could imagine there being less overhead
in a Unix domain socket.

-- 
<Lo-lan-do> Home is where you have to wash the dishes.
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