What is minfree?

The file system minfree space is an area of a UFS file system reserved from users usage, although accessible by root. This area is to allow for commands to be executed on the disk slice (mountpoint).

On very large file systems, the minfree is automatically calculated so that disk space is not wasted.

It is common practice to keep the default 10% minfree value for file systems upto 1GB in size, thereafter adjust the minfree value so the minfree area is no larger than 100MB.

To view 'minfree' value

To view the minfree value of a disk slice, use the following command:

fstyp -v <disk-slice> | grep -i min

For example:

root@schlumpf# fstyp -v /dev/dsk/c0t3d0s0 | grep -i min
minfree 10% maxbpg 2048 optim time

Change the 'minfree' value

To change the minfree value, we use the following command:

tunesfs -m <value> <disk-slice>

For example:

root@schlumpf# tunefs -m 1 /dev/dsk/c0t3d0s0

In the above example, we changed the minimum free space from 10% to 1%. We could also increase the minfree space in the same way as long as there is sufficent physical space available to do so.