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authorLinus Torvalds <torvalds@linux-foundation.org>2013-02-27 20:58:09 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-27 20:58:09 -0800
commit2a7d2b96d5cba7568139d9ab157a0e97ab32440f (patch)
treead029d8cc7b7068b7250e914360ec6315fdfa114 /Documentation/blockdev/nbd.txt
parente3c4877de8b9d93bd47b6ee88eb594b1c1e10da5 (diff)
parentb67bfe0d42cac56c512dd5da4b1b347a23f4b70a (diff)
Merge branch 'akpm' (final batch from Andrew)
Merge third patch-bumb from Andrew Morton: "This wraps me up for -rc1. - Lots of misc stuff and things which were deferred/missed from patchbombings 1 & 2. - ocfs2 things - lib/scatterlist - hfsplus - fatfs - documentation - signals - procfs - lockdep - coredump - seqfile core - kexec - Tejun's large IDR tree reworkings - ipmi - partitions - nbd - random() things - kfifo - tools/testing/selftests updates - Sasha's large and pointless hlist cleanup" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (163 commits) hlist: drop the node parameter from iterators kcmp: make it depend on CHECKPOINT_RESTORE selftests: add a simple doc tools/testing/selftests/Makefile: rearrange targets selftests/efivarfs: add create-read test selftests/efivarfs: add empty file creation test selftests: add tests for efivarfs kfifo: fix kfifo_alloc() and kfifo_init() kfifo: move kfifo.c from kernel/ to lib/ arch Kconfig: centralise CONFIG_ARCH_NO_VIRT_TO_BUS w1: add support for DS2413 Dual Channel Addressable Switch memstick: move the dereference below the NULL test drivers/pps/clients/pps-gpio.c: use devm_kzalloc Documentation/DMA-API-HOWTO.txt: fix typo include/linux/eventfd.h: fix incorrect filename is a comment mtd: mtd_stresstest: use prandom_bytes() mtd: mtd_subpagetest: convert to use prandom library mtd: mtd_speedtest: use prandom_bytes mtd: mtd_pagetest: convert to use prandom library mtd: mtd_oobtest: convert to use prandom library ...
Diffstat (limited to 'Documentation/blockdev/nbd.txt')
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diff --git a/Documentation/blockdev/nbd.txt b/Documentation/blockdev/nbd.txt
index aeb93ffe641..271e607304d 100644
--- a/Documentation/blockdev/nbd.txt
+++ b/Documentation/blockdev/nbd.txt
@@ -4,43 +4,13 @@
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 -
- if you boot from floppy) to borrow disk space from another computer.
- Unlike NFS, it is possible to put any filesystem on it, etc. It should
- even be possible to use NBD as a root filesystem (I've never tried),
- but it requires a user-level program to be in the initrd to start.
- It also allows you to run block-device in user land (making server
- and client physically the same computer, communicating using loopback).
-
- Current state: It currently works. Network block device is stable.
- I originally thought that it was impossible to swap over TCP. It
- turned out not to be true - swapping over TCP now works and seems
- to be deadlock-free, but it requires heavy patches into Linux's
- network layer.
-
+ 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/.
- Howto: To setup nbd, you can simply do the following:
-
- First, serve a device or file from a remote server:
-
- nbd-server <port-number> <device-or-file-to-serve-to-client>
-
- e.g.,
- root@server1 # nbd-server 1234 /dev/sdb1
-
- (serves sdb1 partition on TCP port 1234)
-
- Then, on the local (client) system:
-
- nbd-client <server-name-or-IP> <server-port-number> /dev/nb[0-n]
-
- e.g.,
- root@client1 # nbd-client server1 1234 /dev/nb0
-
- (creates the nb0 device on client1)
-
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