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              (Experimental) Only supported on JFS versions (1.0.18 or  later)
26              that  support external journal.  Attach the JFS external journal
27              located on external-journal to the JFS file system on device.
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29              Currently, you may only attach a single JFS file  system  device
30              to  a  single  JFS  external  journal (i.e. each JFS file system
31              using an external journal must have a unique external journal).
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33              The external journal must already have been  created  using  the
34              command
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36              mkfs.jfs -J journal_dev external-journal
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38              Attach the external journal to the file system by using the com‐
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41              jfs_tune -J device=external-journal device
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43              Instead of specifying a device name  directly,  external-journal
44              can  also  be  specified by either LABEL=label or UUID=UUID (Use
45              jfs_tune -l device to display a journal  device's  volume  label
46              and UUID.)
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49       -l     List  the  contents  of  the JFS file system or external journal
50              superblock that resides on device.
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53       -L volume-label
54              Set the volume label of the JFS file system or external journal.
55              JFS labels can be at most 16 characters long; if volume-label is
56              longer than 16 characters, jfs_tune will truncate it and print a
57              warning.  The volume label can be used by mount(8), fsck(8), and
58              /etc/fstab(5) (and possibly  others)  by  specifying  LABEL=vol‐
59              ume_label instead of a block special device name like /dev/hda5.
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62       -U UUID
63              Set  the universally unique identifier (UUID) of the file system
64              or external journal device to UUID.  The format of the UUID is a
65              series   of   hex   digits  separated  by  hyphens,  like  this:
66              "c1b9d5a2-f162-11cf-9ece-0020afc76f16".  The UUID parameter  may
67              also be one of the following:
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69                   clear  clear the file system UUID
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71                   random generate a new randomly-generated UUID
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73                   time   generate a new time-based UUID
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75              The  UUID  may  be  used by mount(8), fsck(8), and /etc/fstab(5)
76              (and possibly others) by specifying UUID=uuid instead of a block
77              special device name like /dev/hda1.
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79              See uuidgen(8) for more information.
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82       -V     Print version information and exit (regardless of any other cho‐
83              sen options).
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EXAMPLES

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

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

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