GFS consists of the following subsystems: GFS and GNBD.
Table 1-1 summarizes the GFS Software subsystems and their 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. | |
| GNBD | gnbd.ko | Kernel module that implements the GNBD device driver on clients. |
| gnbd_export | Command to create, export and manage GNBDs on a GNBD server. | |
| gnbd_import | Command to import and manage GNBDs on a GNBD client. | |
| gnbd_serv | A server daemon that allows a node to export local storage over the network. |
Table 1-1. GFS Software Subsystem Components