Apparatuses, systems, and methods are disclosed for indexing data of an append-only, log-based structure. A storage controller writes a plurality of data packets to a storage medium by sequentially appending the data packets to a log-based structure of the storage medium. The data packets may be associated with different logical identifiers belonging to a logical address space that is independent of physical storage locations on the storage medium. An indexing module writes an index segment associated with the plurality of data packets to the log-based structure. The index segment may include index entries for determining the logical identifiers of the data packets. The indexing module records, on the storage medium, information indicating where the index segment is written on the storage medium.