A plurality of data storage devices are arranged to form a multi-device array space, and a controller controls access to the array space. The controller is configured to index sets of operational performance data from the plurality of data storage devices into a unified data log. The controller further detects a failure trend of one or more data storage devices by analyzing at least one of a vertical block of data and a horizontal block of data in the unified data log. The vertical data block of data is associated with one of the data storage devices at a plurality of indices. The horizontal block of data is associated with a plurality of the data storage devices at an index.