tunefs(1m) DG/UX 4.30 tunefs(1m)
NAME
tunefs - tune an existing DG/UX file system
SYNOPSIS
/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, max_blks_first_dar
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
max_blks_first_dar 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.blocks_per_dar disk blocks
should be allocated from each
subsequent DAR. The valid range for
max.blks_per_dar is from
max_blocks_first_dar (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 min_free 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 the percentage free
reaches min_free. The valid range
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tunefs(1m) DG/UX 4.30 tunefs(1m)
for min_free is from 1 to 100
percent, however the disk I/O
performance may degrade as the
amount of free space approaches 0
percent.
-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^max_data
blocks at a time. The valid range
for max_data 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^max_dir blocks at at
time. The valid range for max_dir
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^max_idx_data blocks at a
time. The valid range for
max_idx_data 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^max_idx_dir blocks at at
time. The valid range for
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tunefs(1m) DG/UX 4.30 tunefs(1m)
max_idx_dir 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.
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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