docs: blockdev: add it to the admin-guide

The blockdev book basically contains user-faced documentation.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/Documentation/admin-guide/blockdev/nbd.rst b/Documentation/admin-guide/blockdev/nbd.rst
new file mode 100644
index 000000000000..d78dfe559dcf
--- /dev/null
+++ b/Documentation/admin-guide/blockdev/nbd.rst
@@ -0,0 +1,31 @@
+==================================
+Network Block Device (TCP version)
+==================================
+
+1) Overview
+-----------
+
+What is it: With this compiled in the kernel (or as a module), Linux
+can use a remote server as one of its block devices. So every time
+the client computer wants to read, e.g., /dev/nb0, it sends a
+request over TCP to the server, which will reply with the data read.
+This can be used for stations with low disk space (or even diskless)
+to borrow disk space from another computer.
+Unlike NFS, it is possible to put any filesystem on it, etc.
+
+For more information, or to download the nbd-client and nbd-server
+tools, go to http://nbd.sf.net/.
+
+The nbd kernel module need only be installed on the client
+system, as the nbd-server is completely in userspace. In fact,
+the nbd-server has been successfully ported to other operating
+systems, including Windows.
+
+A) NBD parameters
+-----------------
+
+max_part
+	Number of partitions per device (default: 0).
+
+nbds_max
+	Number of block devices that should be initialized (default: 16).