Manual Pages  — TARFS

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

tarfs_load="YES"

The preferred I/O size for tarfs filesystems can be adjusted using the vfs.tarfs.ioshift sysctl setting and tunable. Setting it to 0 will reset it to its default value. Note that changes to this setting only apply to filesystems mounted after the change.

When the backing tar file is compressed with zstd(1), I/O performance can be improved by ensuring that compressed data is broken up into multiple frames. This helps minimize unnecessary decompression work. When using bsdtar(1) to create the tar file, this can be achieved using the zstd:max-frame-size and zstd:frame-per-file options. Sensible frame sizes are powers of 2 between the system's base page size (see arch(7)) and the value of the kern.maxphys sysctl. Smaller frames will generally yield a worse compression ratio and require extra kernel memory to maintain an index, and larger frames will on average require more CPU time to access data when performing random I/O.