xref: /OK3568_Linux_fs/kernel/Documentation/admin-guide/blockdev/nbd.rst (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun==================================
2*4882a593SmuzhiyunNetwork Block Device (TCP version)
3*4882a593Smuzhiyun==================================
4*4882a593Smuzhiyun
5*4882a593Smuzhiyun1) Overview
6*4882a593Smuzhiyun-----------
7*4882a593Smuzhiyun
8*4882a593SmuzhiyunWhat is it: With this compiled in the kernel (or as a module), Linux
9*4882a593Smuzhiyuncan use a remote server as one of its block devices. So every time
10*4882a593Smuzhiyunthe client computer wants to read, e.g., /dev/nb0, it sends a
11*4882a593Smuzhiyunrequest over TCP to the server, which will reply with the data read.
12*4882a593SmuzhiyunThis can be used for stations with low disk space (or even diskless)
13*4882a593Smuzhiyunto borrow disk space from another computer.
14*4882a593SmuzhiyunUnlike NFS, it is possible to put any filesystem on it, etc.
15*4882a593Smuzhiyun
16*4882a593SmuzhiyunFor more information, or to download the nbd-client and nbd-server
17*4882a593Smuzhiyuntools, go to http://nbd.sf.net/.
18*4882a593Smuzhiyun
19*4882a593SmuzhiyunThe nbd kernel module need only be installed on the client
20*4882a593Smuzhiyunsystem, as the nbd-server is completely in userspace. In fact,
21*4882a593Smuzhiyunthe nbd-server has been successfully ported to other operating
22*4882a593Smuzhiyunsystems, including Windows.
23*4882a593Smuzhiyun
24*4882a593SmuzhiyunA) NBD parameters
25*4882a593Smuzhiyun-----------------
26*4882a593Smuzhiyun
27*4882a593Smuzhiyunmax_part
28*4882a593Smuzhiyun	Number of partitions per device (default: 0).
29*4882a593Smuzhiyun
30*4882a593Smuzhiyunnbds_max
31*4882a593Smuzhiyun	Number of block devices that should be initialized (default: 16).
32