1. A system configured to optimize access to stored chunks of data content, the system comprising: a virtual logic unit (vLUN) layer that corresponds to one of a plurality of layers in an input/output (I/O) path of a computer system, the vLUN providing a plurality of logical chunk addresses (LCAs) to layers disposed above it in the I/O path, such that the LCAs in the vLUN are the only LCAs visible to layers above the vLUN; a mapped logical unit (mapped LUN) layer disposed below the vLUN in the I/O path and being in operable communication with the vLUN, the mapped LUN associated with a plurality of physical chunk addresses (PCAs), each PCA configured to provide physical storage for a respective chunk of data; a mapping layer disposed between and in operable communication with the vLUN and the mapped LUN layers, the mapping layer defining a layout of the mapped LUN that helps improve the efficiency of read and write access to the mapped LUN, the layout comprising: a first region comprising a set of first PCAs, each first PCA being allotted to provide physical storage for a respective first chunk of data stored at a single first corresponding LCA in the vLUN, where the first region is reserved for use only by the corresponding LCAs in the vLUN, such that, during a write operation, the first chunk of data is written directly to the first region without requiring location of or allocation of a free PCA to store the first chunk of data; a second region comprising a set of second PCAs, each second PCA being allotted to provide physical storage for a respective second chunk of data, where the second chunk of data corresponds to data that is associated with at least two LCAs; and a metadata region, the metadata region including a first portion indicating, for each LCA in the vLUN, whether the corresponding PCA is located in the first region or the second region of the mapped LUN, and a second portion providing, if the first portion indicates that the corresponding PCA is in the second region of the mapped LUN, mapping information for the LCA to the corresponding PCA in the second region, wherein at least the first portion of the metadata is available in a media that is sufficiently fast, such that, during a read operation, the overhead required to access a chunk of data stored in the first region is zero and the maximum overhead required to access a chunk of data stored in the second region corresponds only to the overhead required to read the mapping information stored in the second portion of the metadata region.