jfs_tune(8)

1jfs_tune(8)             Set JFS file system parameters.            jfs_tune(8)
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NAME

6       jfs_tune - adjust tunable file system parameters on JFS
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SYNOPSIS

10       jfs_tune [options] device
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DESCRIPTION

14       jfs_tune  adjusts  tunable  parameters  on  a  Linux JFS file system or
15       external journal.  jfs_tune must be run as root.
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18       device is the special file name  corresponding  to  the  actual  device
19       (e.g. /dev/hdb1) on which a JFS file system or JFS external journal has
20       been created.
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OPTIONS

24       -J device=external-journal
25              Attach the JFS external journal located on  external-journal  to
26              the JFS file system on device.
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28              The  external  journal  must already have been created using the
29              command.  More than one file system may share the same  external
30              journal.
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32              mkfs.jfs -J journal_dev external-journal
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34              Attach the external journal to the file system by using the com‐
35              mand
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37              jfs_tune -J device=external-journal device
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39              Instead of specifying a device name  directly,  external-journal
40              can  also  be  specified by either LABEL=label or UUID=UUID (Use
41              jfs_tune -l device to display a journal  device's  volume  label
42              and UUID.)
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45       -l     List  the  contents  of  the JFS file system or external journal
46              superblock that resides on device.
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49       -L volume-label
50              Set the volume label of the JFS file system or external journal.
51              JFS labels can be at most 16 characters long; if volume-label is
52              longer than 16 characters, jfs_tune will truncate it and print a
53              warning.  The volume label can be used by mount(8), fsck(8), and
54              /etc/fstab(5) (and possibly  others)  by  specifying  LABEL=vol‐
55              ume_label instead of a block special device name like /dev/hda5.
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58       -U UUID
59              Set  the universally unique identifier (UUID) of the file system
60              or external journal device to UUID.  The format of the UUID is a
61              series   of   hex   digits  separated  by  hyphens,  like  this:
62              "c1b9d5a2-f162-11cf-9ece-0020afc76f16".  The UUID parameter  may
63              also be one of the following:
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65                   clear  clear the file system UUID
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67                   random generate a new randomly-generated UUID
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69                   time   generate a new time-based UUID
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71              The  UUID  may  be  used by mount(8), fsck(8), and /etc/fstab(5)
72              (and possibly others) by specifying UUID=uuid instead of a block
73              special device name like /dev/hda1.
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75              See uuidgen(8) for more information.
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78       -V     Print version information and exit (regardless of any other cho‐
79              sen options).
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EXAMPLES

83       Set a randomly-generated UUID for the JFS file system on the 3rd parti‐
84       tion of the 2nd hard disk, and view the resultant superblock:
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86              jfs_tune -l -U random /dev/hdb3
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88       Attach  an already existing external journal on a device labeled JFSLog
89       to a JFS file system on /dev/hda8:
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91              jfs_tune -J device=LABEL=JFSLog /dev/hda8
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REPORTING BUGS

94       If you find a bug in JFS or jfs_tune, please  report  it  via  the  bug
95       tracking system ("Report Bugs" section) of the JFS project web site:
96       http://jfs.sourceforge.net/
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98       Please  send  as  much  pertinent information as possible including any
99       error messages resulting from running jfs_tune.
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AUTHOR

109       Barry Arndt  (barndt@us.ibm.com)
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111       jfs_tune is maintained by IBM.
112       See the JFS project web site for more details:
113       http://jfs.sourceforge.net/
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117                               October 28, 2002                    jfs_tune(8)