-n|--nodesize <size>
Specify the nodesize, the tree block size in which btrfs stores metadata. The default value is 16KiB (16384) or the page size, whichever is bigger. Must be a multiple of the sectorsize and a power of 2, but not larger than 64KiB (65536). Leafsize always equals nodesize and the options are aliases.

Smaller node size increases fragmentation but leads to taller b-trees which in turn leads to lower locking contention. Higher node sizes give better packing and less fragmentation at the cost of more expensive memory operations while updating the metadata blocks.

Note: versions up to 3.11 set the nodesize to 4k.

-s|--sectorsize <size>
Specify the sectorsize, the minimum data block allocation unit.

The default value is the page size and is autodetected. If the sectorsize differs from the page size, the created filesystem may not be mountable by the kernel. Therefore it is not recommended to use this option unless you are going to mount it on a system with the appropriate page size.