Global File System (GFS) - 4.6. Adding Journals to a File System

4.6. Adding Journals to a File System

The gfs_jadd command is used to add journals to a GFS file system after the device where the file system resides has been expanded. Running a gfs_jadd command on a GFS file system uses space between the current end of the file system and the end of the device where the file system resides. When the fill operation is completed, the journal index is updated.

The gfs_jadd command must be run on mounted file system, but it only needs to be run on one node in the cluster. All the other nodes sense that the expansion has occurred.

To verify that the changes were successful, use the gfs_jadd command with the -T (test) and -v (verbose) flags. Running the command with those flags displays the current state of the mounted GFS file system.

Usage

gfs_jadd -j Number MountPoint

Number: Specifies the number of new journals to be added.
MountPoint: Specifies the directory where the GFS file system is mounted.

Comments

Before running the gfs_jadd command:

Back up important data on the file system.
Run a gfs_tool df MountPoint command to display the volume used by the file system where journals will be added.
Expand the underlying cluster volume with LVM. For information on administering LVM volumes, see the LVM Administrator's Guide

After running the gfs_jadd command, run a gfs_jadd command with the -T and -v flags enabled to check that the new journals have been added to the file system.

Examples

In this example, one journal is added to the file system on the /gfs1 directory.

gfs_jadd -j1 /gfs1

In this example, two journals are added to the file system on the /gfs1 directory.

gfs_jadd -j2 /gfs1

In this example, the current state of the file system on the /gfs1 directory is checked for the new journals.

gfs_jadd -Tv /gfs1

Complete Usage

gfs_jadd [Options] {MountPoint | Device} [MountPoint | Device]

MountPoint: Specifies the directory where the GFS file system is mounted.
Device: Specifies the device node of the file system.

Table 4.4, “GFS-specific Options Available When Adding Journals” describes the GFS-specific options that can be used when adding journals to a GFS file system.

Flag	Parameter	Description
`-h`		Help. Displays short usage message.
`-J`	`MegaBytes`	Specifies the size of the new journals in megabytes. Default journal size is 128 megabytes. The minimum size is 32 megabytes. To add journals of different sizes to the file system, the `gfs_jadd` command must be run for each size journal. The size specified is rounded down so that it is a multiple of the journal-segment size that was specified when the file system was created.
`-j`	`Number`	Specifies the number of new journals to be added by the `gfs_jadd` command. The default value is 1.
`-T`		Test. Do all calculations, but do not write any data to the disk and do not add journals to the file system. Enabling this flag helps discover what the `gfs_jadd` command would have done if it were run without this flag. Using the `-v` flag with the `-T` flag turns up the verbosity level to display more information.
`-q`		Quiet. Turns down the verbosity level.
`-V`		Displays command version information.
`-v`		Turns up the verbosity of messages.

Table 4.4. GFS-specific Options Available When Adding Journals