Red Hat GFS 6.0 -, Administrator'S Manual

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Chapter 1. Red Hat GFS Overview 5
LAN
Clients
GNBD
servers
Disk
A
GFS
Applications
Disk
B
Disk
D
Disk
C
Disk
E
Disk
F
Shared Files
Figure 1-3. GFS and GNBD with Directly Connected Storage
1.3. GFS Functions
GFS is a native file system that interfaces directly with the VFS layer of the Linux kernel file-system
interface. GFS is a cluster file system that employs distributed metadata and multiple journals for
optimal operation in a cluster.
GFS provides the following main functions:
•
Cluster volume management
•
Lock management
•
Cluster management, fencing, and recovery
•
Cluster configuration management
1.3.1. Cluster Volume Management
Cluster volume management provides simplified management of volumes and the ability to dynam-
ically extend file system capacity without interrupting file-system access. With cluster volume man-
agement, you can aggregate multiple physical volumes into a single, logical device across all nodes in
a cluster.
Cluster volume management provides a logical view of the storage to GFS, which provides flexibility
for the administrator in how the physical storage is managed. Also, cluster volume management pro-
vides increased availability because it allows increasing the storage capacity without shutting down
the cluster. Refer to Chapter 5 Using the Pool Volume Manager for more information about cluster
volume management.