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34cman has been replaced by the dlm package.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