A logical object is the single thing a system intends to represent, even when its representation or storage is divided among multiple physical objects. Replication asks whether physical entities still represent the same logical item; partitioning divides one logical object into disjoint physical objects. section 8.2 section 7.2
An encyclopedia in volumes
An encyclopedia is one logical object, while its alphabetically organized volumes are physical objects containing disjoint subsets of entries. The arrangement makes lookup possible, but uneven volume sizes, uneven demand, and cross-references create practical challenges. A software dataset can use the same model by distributing partitions across nodes. section 7.1
Figure 7.1 Encyclopedias and volumes
Use the figure to visualize one logical encyclopedia represented by multiple physical volumes. section 7.1
