Installation guide

Software Subsystem Components Description

file system. This command can also gath-

er a variety of information about the file

system.

lock_harness.ko Implements a pluggable lock module in-

terface for GFS that allows for a variety of

locking mechanisms to be used (for ex-

ample, the DLM lock module,

lock_dlm.ko).

lock_dlm.ko A lock module that implements DLM lock-

ing for GFS. It plugs into the lock har-

ness, lock_harness.ko and communic-

ates with the DLM 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.

Table 1.1. GFS Software Subsystem Components

5. Before Setting Up GFS

Before you install and set up GFS, note the following key characteristics of your GFS file sys-

tems:

Number of file systems

Determine how many GFS file systems to create initially. (More file systems can be added

later.)

File-system name

Determine a unique name for each file system. Each file-system name is required in the

form of a parameter variable. For example, this book uses file-system names gfs1 and gfs2

in some example procedures.

Journals

Determine the number of journals for your GFS file systems. One journal is required for

each node that mounts a GFS file system. Make sure to account for additional journals

needed for future expansion.

GFS nodes

Determine which nodes in the Red Hat Cluster Suite will mount the GFS file systems.

GNBD server nodes

If you are using GNBD, determine how many GNBD server nodes are needed. Note the

5. Before Setting Up GFS