minfreespace

default: 4G

minfreespace is used to set a minimum free space threshold when running create policies. Any branch with free space less than the minfreespace value will be skipped. This is the global default but individual branches can have their own value..

This is useful for a couple reasons.

• Since mergerfs does not split files across branches it is best to leave space to write a newly created file on a branch to minimize the risk of running out of space and needing moveonenospc.
• Some filesystems' performance degrades when filled. minfreespace provides a buffer so they are less likely to be filled.
• Similar to ext4's reserved space option it minimizes the problems that come from running out of space.