tunefs(1M) DG/UX R4.11MU05 tunefs(1M)
NAME
tunefs - tune an existing file system
SYNOPSIS
/etc/tunefs [option ...] filesys|special
where:
option -e, -E, -m, -s, -S, -e, -x, or -X, followed by an argument.
filesys The pathname of the directory with which the file system is
associated in the file /etc/fstab
special The pathname of a special file referring to a device
containing a file system
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). The file system must be unmounted.
Options are:
-e maxblksfirstdar 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 maxblksperdar 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 minfree Specifies the minimum percentage of the file
system that should be maintained as free
space. Only processes with appropriate
privlege may allocate these blocks. (See
NOTES, below.) If minfree is greater than the
percentage of space currently free, then
processes without appropriate privlege will
not be able to allocate any blocks on the file
system until the percentage free reaches
minfree. The valid range for minfree is
from 1 to 100 percent; however, the disk I/O
performance may degrade as the amount of free
space approaches 0 percent.
Note that file system space is counted in
blocks rather than bytes. As a result, tunefs
might not be able to reserve the exact
percentage of free space specified with this
option. It will round the free space
percentage to a value that represents a whole
number of blocks.
-s maxdata 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
0 to the log of the number of user blocks per
disk allocation region in the file system.
-S maxdir 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 a time. The valid range
for maxdir is from 0 to the log of the number
of user blocks per disk allocation region in
the file system.
-x maxidxdata 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 0 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 maxidxdir 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 0 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.
NOTES
On a generic DG/UX system, appropriate privilege is granted by having
an effective UID of 0 (root). See the appropriateprivilege(5) man
page for more information.
On a system with DG/UX information security, appropriate privilege is
granted by having one or more specific capabilities enabled in the
effective capability set of the user. See the capdefaults(5) man
page for more information.
SEE ALSO
fsck(1M), mkfs(1M), fstab(4), cpd(1), appropriateprivilege(5).
BUGS
Tunefs cannot be run on the root file system because that system
cannot be unmounted.
Tunefs can be used to tune the usr file system, but (since it is
located in /usr/sbin) it must be copied to a directory in the root
file system (like /tmp) and invoked from there.
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