1Global File System
   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.
  14GFS uses interchangeable inter-node locking mechanisms, the currently
  15supported mechanisms are:
  17  lock_nolock -- allows gfs to be used as a local file system
  19  lock_dlm -- uses a distributed lock manager (dlm) for inter-node locking
  20  The dlm is found at linux/fs/dlm/
  22Lock_dlm depends on user space cluster management systems found
  23at the URL above.
  25To use gfs as a local file system, no external clustering systems are
  26needed, simply:
  28  $ mkfs -t gfs2 -p lock_nolock -j 1 /dev/block_device
  29  $ mount -t gfs2 /dev/block_device /dir
  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  34cman has been replaced by the dlm package.
  36GFS2 is not on-disk compatible with previous versions of GFS, but it
  37is pretty close.
  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
  46 kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.