1.3. GFS Software Subsystems

Table 1.1, “GFS Software Subsystem Components” summarizes the GFS Software subsystems and their components.

Table 1.1. GFS Software Subsystem Components
Software Subsystem	Components	Description
GFS	`gfs.ko`	Kernel module that implements the GFS file system and is loaded on GFS cluster nodes.
	`gfs_fsck`	Command that repairs an unmounted GFS file system.
	`gfs_grow`	Command that grows a mounted GFS file system.
	`gfs_jadd`	Command that adds journals to a mounted GFS file system.
	`gfs_mkfs`	Command that creates a GFS file system on a storage device.
	`gfs_quota`	Command that manages quotas on a mounted GFS file system.
	`gfs_tool`	Command that configures or tunes a GFS file system. This command can also gather a variety of information about the file system.
	`lock_harness.ko`	Implements a pluggable lock module interface for GFS that allows for a variety of locking mechanisms to be used (for example, the DLM lock module, `lock_dlm.ko`).
	`lock_dlm.ko`	A lock module that implements DLM locking for GFS. It plugs into the lock harness, `lock_harness.ko` and communicates with the DLM lock manager in Red Hat Cluster Suite.
	`lock_gulm.ko`	A lock module that implements GULM locking for GFS. It plugs into the lock harness, `lock_harness.ko` and communicates with the GULM lock manager in Red Hat Cluster Suite.
	`lock_nolock.ko`	A lock module for use when GFS is used as a local file system only. It plugs into the lock harness, `lock_harness.ko` and provides local locking.