|Global File System
|GFS is a cluster file system. It allows a cluster of computers to
|simultaneously use a block device that is shared between them (with FC,
|iSCSI, NBD, etc). GFS reads and writes to the block device like a local
|file system, but also uses a lock module to allow the computers coordinate
|their I/O so file system consistency is maintained. One of the nifty
|features of GFS is perfect consistency -- changes made to the file system
|on one machine show up immediately on all other machines in the cluster.
|GFS uses interchangable inter-node locking mechanisms, the currently
|supported mechanisms are:
| lock_nolock -- allows gfs to be used as a local file system
| lock_dlm -- uses a distributed lock manager (dlm) for inter-node locking
| The dlm is found at linux/fs/dlm/
|Lock_dlm depends on user space cluster management systems found
|at the URL above.
|To use gfs as a local file system, no external clustering systems are
| $ mkfs -t gfs2 -p lock_nolock -j 1 /dev/block_device
| $ mount -t gfs2 /dev/block_device /dir
|If you are using Fedora, you need to install the gfs2-utils package
|and, for lock_dlm, you will also need to install the cman package
|and write a cluster.conf as per the documentation.
|GFS2 is not on-disk compatible with previous versions of GFS, but it
|is pretty close.
|The following man pages can be found at the URL above:
| fsck.gfs2 to repair a filesystem
| gfs2_grow to expand a filesystem online
| gfs2_jadd to add journals to a filesystem online
| gfs2_tool to manipulate, examine and tune a filesystem
| gfs2_quota to examine and change quota values in a filesystem
| gfs2_convert to convert a gfs filesystem to gfs2 in-place
| mount.gfs2 to help mount(8) mount a filesystem
| mkfs.gfs2 to make a filesystem