tunefs(1m)
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tunefs
tune an existing DG/UX file system
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SYNTAX
/etc/tunefs options filesys | special
DESCRIPTION
Tunefs changes the dynamic parameters of a file system that
affect the layout policies. Defaults are set according to the
values established by mkfs(1m). Filesys is the pathname of the
directory with which the file system is associated in the file
/etc/fstab. Special is the pathname of a special file referring
to a device containing a file system. The file system must be
unmounted.
Options are:
-e max_blks_first_dar
Specifies that when allocating disk space for
a file, maxblksfirstdar disk blocks should
be allocated from the disk allocation region
(DAR) chosen for the initial file space
allocation, before moving on to another DAR.
The valid range for maxblksfirstdar is
from 1 to the number of available disk blocks
in the DAR.
-E max_blks_per_dar Specifies that when allocating disk space for
a file, after the initial disk allocation
region (DAR) has been exhausted (see the -e
option), then max.blocksperdar disk blocks
should be allocated from each subsequent DAR.
The valid range for max.blksperdar is from
maxblocksfirstdar (see the -e option) to
the number of available disk blocks in the
DAR.
-m min_free Specifies the minimum percentage of the file
system that should be maintained as free
space. Only superuser processes may allocate
these blocks. If minfree is greater than
the percentage of space currently free, then
non-superuser processes will not be able to
allocate any blocks on the file system until
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tunefs(1m)
the percentage free reaches minfree. The
valid range for min_free is from 0% to 100%,
however the disk i/o performance may degrade
as the amount of free space approaches 0%.
-s max_data Specifies the block size for a file's data
blocks on the file system, given as log base
2 of the block size. The disk space for a
file's data is allocated 2^maxdata blocks at
a time. The valid range for maxdata is from
1 to the log of the number of user blocks per
disk allocation region in the file system.
-S max_dir Specifies the block size for directories on
the file system, given as log base 2 of the
block size. The disk space for the file
system's directory blocks is allocated
2^maxdir blocks at at time. The valid range
for maxdir is from 1 to the log of the
number of user blocks per disk allocation
region in the file system.
-x max_idx_data Specifies the block size for a file's index
blocks (the space used for addressing a
file's data blocks) in the file system, given
as log base 2 of the block size. The disk
space for a file's index blocks is allocated
2^maxidxdata blocks at a time. The valid
range for maxidxdata is from 1 to the log
of the number of blocks available for use as
index blocks per disk allocation region
(DAR), which is usually less than the number
of user blocks per DAR.
-X max_idx_dir Specifies the block size for the file
system's index blocks (the space used for
addressing a directory's blocks) in the file
system, given as log base 2 of the block
size. The disk space for a directory's index
blocks is allocated 2^maxidxdir blocks at
at time. The valid range for maxidxdir is
from 1 to the log of the number of blocks
available for use as index blocks per disk
allocation region (DAR), which is usually
less than the number of user blocks per DAR.
Specifying an invalid option value causes the program to print
the valid range of values for that option and then exit.
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tunefs(1m)
SEE ALSO
fsck(1m), mkfs(1m), fstab(4).
BUGS
Tunefs cannot be run on the root file system because that system
cannot be unmounted.
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