wok-current diff nbd/description.txt @ rev 24992
Up sip (4.19.25)
author | Pascal Bellard <pascal.bellard@slitaz.org> |
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date | Sat May 14 18:19:29 2022 +0000 (2022-05-14) |
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1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 1.2 +++ b/nbd/description.txt Sat May 14 18:19:29 2022 +0000 1.3 @@ -0,0 +1,21 @@ 1.4 +With this compiled into your kernel, Linux can use a remote server 1.5 +as one of its block devices. 1.6 +Every time the client computer wants to read /dev/nbd0, it will send 1.7 +a request to the server via TCP, which will reply with the data 1.8 +requested. 1.9 +This can be used for stations with low disk space (or even diskless 1.10 +- if you use an initrd) to borrow disk space from other computers. 1.11 +Unlike NFS, it is possible to put any file system on it. 1.12 +But (also unlike NFS), if someone has mounted NBD read and write, 1.13 +you must assure that no one else will have it mounted. 1.14 + 1.15 +Current state: 1.16 +It currently works. Network block device is pretty stable. 1.17 +It was originaly thought that it is impossible to swap over TCP; 1.18 +this turned out not to be true. 1.19 +However, to avoid deadlocks, you will need at least Linux 3.6. 1.20 + 1.21 +It is possible to use NBD as the block device counterpart of FUSE, 1.22 +to implement the block device's reads and writes in user space. 1.23 +To make this easer, recent versions of NBD (3.10 and above) 1.24 +implement NBD over a Unix Domain Socket, too.