# OpenGFS file system interface module

The OpenGFS FSIM lets EVMS users create and manage OpenGFS file systems from within the EVMS interfaces. In order to use the OpenGFS FSIM, the OpenGFS utilities must be installed on your system. Go to http://sourceforge.net/projects/opengfs for the OpenGFS project.

## Creating OpenGFS file systems

OpenGFS file systems can be created with `mkfs` on any EVMS or compatibility volume that does not already have a file system and that is produced from a shared cluster container. The following options are available for creating OpenGFS file systems:

blocksize

  Set the file system block size. The block size is in bytes. The block size must be a power of 2 between 512 and 65536, inclusive. The default block size is 4096 bytes.

journals

  The names of the journal volumes, one for each node.

protocol

  Specify the name of the locking protocol to use. The choices are "memexp" and "opendlm."

lockdev

  Specify the shared volume to be used to contain the locking metadata.

The OpenGFS FSIM only takes care of file system operations. It does not take care of OpenGFS cluster and node configuration. Before the volumes can be mounted, you must configure the cluster and node separately after you have made the file system and saved the changes.

## Checking OpenGFS file systems

The OpenGFS utility for checking the file system has no additional options.

## Removing OpenGFS file systems

An OpenGFS file system can be removed from its volume if the file system is unmounted. This operation involves erasing the superblock from the volume, erasing the log headers for the journal volumes, and erasing the control block on the cluster configuration volume associated with the file system volume so that the file system will not be recognized in the future. There are no options available for removing file systems.

## Expanding and shrinking OpenGFS file systems

OpenGFS only allows a volume to be expanded. OpenGFS only allows a volume to expanded when the volume is mounted. An OpenGFS file system is automatically expanded when its volume is expanded.