# On-disk collection structure

See [obilayeredmap crate](obilayeredmap.md) for the current on-disk layout.

The index root contains one `part_XXXXX/` directory per partition, each holding one or more `layer_N/` directories. Each layer directory contains `mphf.bin`, `unitigs.bin`, `unitigs.bin.idx`, `evidence.bin`, and optionally a `counts/` or `presence/` payload directory.