1. A transaction-logging data storage system comprising: a data storage subsystem that stores variable-size data objects, wherein the data storage subsystem is implemented using: one or more storage devices comprising: an array of data storage units, wherein the array is configured to provide one or more ranks, each of the one or more ranks providing stripes for storing data objects; and a rank manager that performs configuration processing associated with the one or more ranks; wherein the data storage subsystem is configured to write data corresponding to each of the stripes into the one or more ranks as a unit; a stripe space component including a stripe space table that keeps track of space usage in the data storage subsystem; a mapping component that processes mapping information between data object identifiers and physical address information of the data objects within the data storage subsystem; and at least one processing component that performs operations among the data storage subsystem, the mapping component and the stripe space table, wherein the operations are coordinated to implement logging data objects to be stored and logging changes to stored data objects; wherein the at least one processing component includes a subcomponent that allocates storage as a function of one or more characteristics associated with a rank selected from the group of characteristics composed of load sharing characteristics, usage characteristics, and/or performance characteristics.