jfs_tune(8) Set JFS file system parameters. jfs_tune(8)NAMEjfs_tune - adjust tunable file system parameters on JFS
SYNOPSISjfs_tune [options] device
DESCRIPTIONjfs_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.
OPTIONS-J device=external-journal
Only supported on JFS versions (1.0.18 or later) that support
external journal. Attach the JFS external journal located on
external-journal to the JFS file system on device.
Currently, you may only attach a single JFS file system device
to a single JFS external journal (i.e. each JFS file system
using an external journal must have a unique external journal).
The external journal must already have been created using the
command
mkfs.jfs -J journal_dev external-journal
Attach the external journal to the file system by using the com‐
mand
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.)
-l 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=vol‐
ume_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 clear the file system UUID
random generate a new randomly-generated UUID
time 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.
-V Print version information and exit (regardless of any other cho‐
sen options).
EXAMPLES
Set a randomly-generated UUID for the JFS file system on the 3rd parti‐
tion 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:
http://jfs.sourceforge.net/
Please send as much pertinent information as possible including any
error messages resulting from running jfs_tune.
SEE ALSOjfs_fsck(8), jfs_mkfs(8), jfs_fscklog(8), jfs_logdump(8),
jfs_debugfs(8)AUTHOR
Barry Arndt (barndt@us.ibm.com)
jfs_tune is maintained by IBM.
See the JFS project web site for more details:
http://jfs.sourceforge.net/
October 28, 2002 jfs_tune(8)
