(Partially taken from the nbd-source)
You have to have support for CONFIG_BLK_DEV_NBD in your kernel.
Since there's a problem with nbd and the cfq I/O scheduler,
you may want to set it to deadline:
echo 'deadline' > /sys/block/nbd0/queue/scheduler
(repeat the above for nbd1, nbd2, etc, if you need more than one device)
Next, start the server. You can use a file or a block device for that, e.g.
nbd-server 1234 /home/wouter/nbd-export
Note that the filename must be an absolute path; i.e., something like
/path/to/file, not ../file. See the nbd-server manpage for details on
any available options.
Finally, you'll be able to start the client, e.g.
nbd-client 10.0.0.1 1234 /dev/nb0
nbd-client must be ran as root; the same is not true for nbd-server (but
do make sure that /var/run is writeable by the server that nbd-server
runs as; otherwise, you won't get a PID file, though the server will
keep running).
nbd-server can be configured by modifying
/etc/nbd-server/config, and should look something like this:
# This is a comment
[generic]
# The [generic] section is required, even if nothing is specified
# there.
# When either of these options are specified, nbd-server drops
# privileges to the given user and group after opening ports, but
# _before_ opening files.
user = nbd
group = nbd
[export1]
exportname = /export/nbd/export1-file
port = 12345
authfile = /export/nbd/export1-authfile
timeout = 30
filesize = 10000000
readonly = false
multifile = false
copyonwrite = false
prerun = dd if=/dev/zero of=%s bs=1k count=500
postrun = rm -f %s
[otherexport]
exportname = /export/nbd/experiment
port = 12346
# The other options are all optional.
extended documentation can be found in nbd-server(5)
