Provided by: jfsutils_1.1.15-2.1_i386 bug

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.

OPTIONS

       -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.)

       -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=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  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
              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:
       http://jfs.sourceforge.net/

       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)

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)