[ENBD] Local mounting of devices

[Peter T. Breuer]

"A month of sundays ago Alexandru COSTIN wrote:"
>     Anyway, I am interested if there is any way of mounting a remote
> formatted device on the local computer, without using TCP/IP and the server
> and client. I am interested in this thing to save resources when mounting
> local files as devices on the same computer they are stored).

I'm not sure what you mean here. You can format the resource at the remote end,
then export it via NBD. You don't have to format it _over_ the nbd device.

On the other hand, if you are talking about loopback mounts, why not use
loopback mounts (mount -o loop -t extfs myfile /mnt, or losetup and friends)?

>     More, I've discovered some strage lookups on the client computer when
> trying to install windows 2000 on a vmware machine that has a enbd raw disk.
>     I mean I've exported from one computer a file of 1.6 Gigs and mounted it
> on other computer(/dev/nda). On the second computer (running 2.2.18pre15)
> tryied to install Windows 2000 in a VMWare process, configured with /dev/nda
> as a RAW disc. It completely froze the second computer several times, and it
> work now only after downgrading to 2.2.17.

The kernel should not influence things since the module does very
standard things, but if indeed someone has done something to the kernel
lately in the block device area that affects either nbd or vmware, you
should let Alan Cox know at once.  He will almost certainly ask you to
interpolate between patch sets to locate the discontinuity (and I'd
advise you to A) check what vmware modules you are loading and where you
got them from, and B) to watch out for changes in ll_blk_rw.c).  I
haven't proceeded beyond kernel 2.2.15 myself, though I'm willing to
try, say, 2.2.17 if paid danger money (I'm conservative about such things).

>     Regarding the first question, it would be possible to mount the disk on
> the first computer (to link /dev/nda to the file without starting a server
> and a process) ?? It would be nice to save some TCP/IP stack overhead.

Err .. I think you ARE talking about loopback mounts. Man losetup. Man
mount (-o loop).

Peter