GFS is a cluster file system that provides data sharing among Linux-based computers. GFS provides a single, consistent view of the file system name space across all nodes in a cluster. It allows applications to install and run without much knowledge of the underlying storage infrastructure. GFS is fully compliant with the IEEE POSIX interface, allowing applications to perform file operations as if they were running on a local file system. Also, GFS provides features that are typically required in enterprise environments, such as quotas, multiple journals, and multipath support.
GFS provides a versatile method of networking your storage according to the performance, scalability, and economic needs of your storage environment.
This chapter provides some very basic, abbreviated information as background to help you understand GFS. It contains the following sections:
New for this release are the following functions:
File access control lists (ACLs) and extended file attributes in GFS file systems — This release adds the capability of setting and getting file ACLs and extended file attributes in a GFS file system. The Linux commands setfacl and getfacl set and get ACLs. The Linux commands setfattr and getfattr set and get file attributes. In addition, this release adds a GFS-specific mount command option, -o acl. The new option allows users to set ACLs. For more information about the -o acl option, refer to Section 9.2 Mounting a File System.
Additional fencing agents — This release adds fencing agents for McData Fibre Channel (FC) switches, Egenera BladeFrame systems, and xCAT (Extreme Cluster Administration Toolkit) clusters.
Initialization scripts — This release adds init.d scripts for the pool, ccsd, lock_gulmd, and gfs modules. For more information about the scripts, refer to Chapter 12 Using GFS init.d Scripts.
Sub-second node failure detection — This release allows configuring the GFS cluster heartbeat rate for sub-second node failure detection. For more information, refer to Section 6.5 Creating the cluster.ccs File.
Removal of license mechanism — Previous GFS releases required a license file that defined the term of use and which GFS features were enabled. This release does not require a license file.
Initial-configuration druid via Red Hat Cluster Suite — When GFS is installed with Red Hat Cluster Suite, a configuration druid is available with Cluster Suite for initial configuration of GFS. For more information about the druid, refer to the Cluster Suite documentation.
For information about using GFS with Red Hat Cluster Suite, refer to Appendix A Using Red Hat GFS with Red Hat Cluster Suite. For GFS upgrade instructions, refer to Appendix B Upgrading GFS.