GFS Overview
The Red Hat GFS file system is a native file system that interfaces directly with the Linux kernel
file system interface (VFS layer). A GFS file system can be implemented in a standalone system
or as part of a cluster configuration. When implemented as a cluster file system, GFS employs
distributed metadata and multiple journals.
A GFS file system can be created on an LVM logical volume. A logical volume is an aggregation
of underlying block devices that appears as a single logical device. For information on the LVM
volume manager, see the LVM Administrator's Guide.
GFS is based on a 64-bit architecture, which can theoretically accommodate an 8 EB file
system. However, the current supported maximum size of a GFS file system is 25 TB. If your
system requires GFS file systems larger than 25 TB, contact your Red Hat service
representative.
When determining the size of your file system, you should consider your recovery needs.
Running the
fsck
command on a very large file system can take a long time and consume a
large amount of memory. Additionally, in the event of a disk or disk-subsytem failure, recovery
time is limited by the speed of your backup media.
When configured in a Red Hat Cluster Suite, Red Hat GFS nodes can be configured and
managed with Red Hat Cluster Suite configuration and management tools. Red Hat GFS then
provides data sharing among GFS nodes in a Red Hat cluster, with a single, consistent view of
the file system name space across the GFS nodes. This allows processes on different nodes to
share GFS files in the same way that processes on the same node can share files on a local file
system, with no discernible difference. For information about Red Hat Cluster Suite refer to
Configuring and Managing a Red Hat Cluster.
LVM logical volumes in a Red Hat Cluster suite are managed with CLVM, which is a
cluster-wide implementation of LVM, enabled by the CLVM daemon,
clvmd
running in a Red
Hat Cluster Suite cluster. The daemon makes it possible to use LVM to manage logical volumes
across a cluster, allowing all nodes in the cluster to share the logical volumes. to any directory
on your system. For information on the LVM volume manager, see the LVM Administrator's
Guide.
This chapter provides some basic, abbreviated information as background to help you
understand GFS. It contains the following sections:
•
Section 1, “New and Changed Features”
•
Section 2, “Performance, Scalability, and Economy”
•
Section 3, “GFS Software Components”
•
Section 4, “Before Setting Up GFS”
Chapter 1.
1
Содержание GLOBAL FILE SYSTEM 5.2
Страница 4: ...Global File System...
Страница 6: ...vi...
