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Diffstat (limited to 'Documentation/blockdev')
| -rw-r--r-- | Documentation/blockdev/nbd.txt | 38 |
1 files changed, 4 insertions, 34 deletions
diff --git a/Documentation/blockdev/nbd.txt b/Documentation/blockdev/nbd.txt index aeb93ffe6416..271e607304da 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 |