1.. SPDX-License-Identifier: GPL-2.0
2
3==================
4Global File System
5==================
6
7https://fedorahosted.org/cluster/wiki/HomePage
8
9GFS is a cluster file system. It allows a cluster of computers to
10simultaneously use a block device that is shared between them (with FC,
11iSCSI, NBD, etc).  GFS reads and writes to the block device like a local
12file system, but also uses a lock module to allow the computers coordinate
13their I/O so file system consistency is maintained.  One of the nifty
14features of GFS is perfect consistency -- changes made to the file system
15on one machine show up immediately on all other machines in the cluster.
16
17GFS uses interchangeable inter-node locking mechanisms, the currently
18supported mechanisms are:
19
20  lock_nolock
21    - allows gfs to be used as a local file system
22
23  lock_dlm
24    - uses a distributed lock manager (dlm) for inter-node locking.
25      The dlm is found at linux/fs/dlm/
26
27Lock_dlm depends on user space cluster management systems found
28at the URL above.
29
30To use gfs as a local file system, no external clustering systems are
31needed, simply::
32
33  $ mkfs -t gfs2 -p lock_nolock -j 1 /dev/block_device
34  $ mount -t gfs2 /dev/block_device /dir
35
36If you are using Fedora, you need to install the gfs2-utils package
37and, for lock_dlm, you will also need to install the cman package
38and write a cluster.conf as per the documentation. For F17 and above
39cman has been replaced by the dlm package.
40
41GFS2 is not on-disk compatible with previous versions of GFS, but it
42is pretty close.
43
44The following man pages can be found at the URL above:
45
46  ============		=============================================
47  fsck.gfs2		to repair a filesystem
48  gfs2_grow		to expand a filesystem online
49  gfs2_jadd		to add journals to a filesystem online
50  tunegfs2		to manipulate, examine and tune a filesystem
51  gfs2_convert		to convert a gfs filesystem to gfs2 in-place
52  mkfs.gfs2		to make a filesystem
53  ============		=============================================
54