tunefs [-a maxcontig] [-d rotdelay] [-e maxbpg] [-m minfree] [-o space | time] special | filesystem
tunefs is designed to change the dynamic parameters of a file system that affect the layout policies. When using tunefs with filesystem, filesystem must be in /etc/vfstab. The parameters that can be changed are indicated by the options given below.
The following options are supported:
maxcontig = disk drive maximum transfer size / disk block size
If the disk drive's maximum transfer size cannot be determined, the default value for maxcontig is calculated from kernel parameters as follows:
If maxphys is less than ufs_maxmaxphys, which is 1 Mbyte, then maxcontig is set to maxphys. Otherwise, maxcontig is set to ufs_maxmaxphys.
You can set maxcontig to any positive integer value.
The actual value will be the lesser of what has been specified and what the hardware supports.
The effect of this limit is to cause big files to do long seeks more frequently than if they were allowed to allocate all the blocks in a cylinder group before seeking elsewhere. For file systems with exclusively large files, this parameter should be set higher.
Generally, you should optimize for time unless the file system is over 90% full.
See largefile(5) for the description of the behavior of tunefs when encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).
|December 5, 2003||OmniOS|