|jfs_tune(8)||Set JFS file system parameters.||jfs_tune(8)|
NAME¶jfs_tune - adjust tunable file system parameters on JFS
SYNOPSIS¶jfs_tune [options] device
DESCRIPTION¶jfs_tune adjusts tunable parameters on a Linux JFS file system or external journal. jfs_tune must be run as root.
device is the special file name corresponding to the actual device (e.g. /dev/hdb1) on which a JFS file system or JFS external journal has been created.
- -J device=external-journal
- Attach the JFS external journal located on external-journal to the JFS file system on device.
- The external journal must already have been created using the command. More than one file system may share the same external journal.
- mkfs.jfs -J journal_dev external-journal
- Attach the external journal to the file system by using the command
- jfs_tune -J device=external-journal device
- Instead of specifying a device name directly, external-journal can also be specified by either LABEL=label or UUID=UUID (Use jfs_tune -l device to display a journal device's volume label and UUID.)
- List the contents of the JFS file system or external journal superblock that resides on device.
- -L volume-label
- Set the volume label of the JFS file system or external journal. JFS labels can be at most 16 characters long; if volume-label is longer than 16 characters, jfs_tune will truncate it and print a warning. The volume label can be used by mount(8), fsck(8), and /etc/fstab(5) (and possibly others) by specifying LABEL=volume_label instead of a block special device name like /dev/hda5.
- -U UUID
- Set the universally unique identifier (UUID) of the file system or external journal device to UUID. The format of the UUID is a series of hex digits separated by hyphens, like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16". The UUID parameter may also be one of the following:
- clear the file system UUID
- generate a new randomly-generated UUID
- generate a new time-based UUID
- The UUID may be used by mount(8), fsck(8), and /etc/fstab(5) (and possibly others) by specifying UUID=uuid instead of a block special device name like /dev/hda1.
- See uuidgen(8) for more information.
- Print version information and exit (regardless of any other chosen options).
EXAMPLES¶Set a randomly-generated UUID for the JFS file system on the 3rd partition of the 2nd hard disk, and view the resultant superblock:
- jfs_tune -l -U random /dev/hdb3
Attach an already existing external journal on a device labeled JFSLog to a JFS file system on /dev/hda8:
- jfs_tune -J device=LABEL=JFSLog /dev/hda8
REPORTING BUGS¶If you find a bug in JFS or jfs_tune, please report it via the bug tracking system ("Report Bugs" section) of the JFS project web site:
Please send as much pertinent information as possible including any error messages resulting from running jfs_tune.
SEE ALSO¶jfs_fsck(8), jfs_mkfs(8), jfs_fscklog(8), jfs_logdump(8), jfs_debugfs(8)
Barry Arndt (firstname.lastname@example.org)jfs_tune is maintained by IBM.
See the JFS project web site for more details: http://jfs.sourceforge.net/
|October 28, 2002|