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