Subject: Re: NBD was Re: [PATCH 00/33] Swap over NFS -v14

From: Peter Zijlstra <[email-masked]>
Date: Wed, 31 Oct 2007 12:24:49 +0100

On Wed, 2007-10-31 at 12:18 +0100, Pavel Machek wrote:
> Hi!
> 
> > > So please get the VM bits for swap over network blockdevices in first,
> > 
> > Trouble with that part is that we don't have any sane network block
> > devices atm, NBD is utter crap, and iSCSI is too complex to be called
> > sane.
> 
> Hey, NBD was designed to be _simple_. And I think it works okay in
> that area.. so can you elaborate on "utter crap"? [Ok, performance is
> not great.]

Yeah, sorry, perhaps I was overly strong.

It doesn't work for me, because:

  - it does connection management in user-space, which makes it
    impossible to reconnect. I'd want a full kernel based client.

  - it had some plugging issues, and after talking to Jens about it
    he suggested a rewrite using ->make_request() ala AoE. [ sorry if
    I'm short on details here, it was a long time ago, and I
    forgot, maybe Jens remembers ]

> Plus, I'd suggest you to look at ata-over-ethernet. It is in tree
> today, quite simple, but should have better performance than nbd.

Ah, right, I keep forgetting about that one. The only draw-back to that
on is, is that its raw ethernet, and not some IP protocol.