Example apparatus and methods provide a log structured block device for a hard disk drive (HDD). Data that is to be stored on an HDD is serialized and written as a series of data blocks using a sequential write. Information about where individual data blocks were supposed to be written (e.g., actual address, neighboring data blocks), where data blocks were actually written, and how often data blocks are accessed is maintained. During garbage collection, data blocks that are being accessed with similar frequencies may be relocated together, with the most frequently accessed (e.g., hottest) data blocks migrating to the outer cylinders of the disk and the least frequently accessed (e.g., coldest) data blocks migrating to the inner cylinders. Blocks stored in the same temperature regions that were intended to be located together when written may be repositioned to facilitate sequential reads.