  Digital contents in large scale distributed storage systems may have
different reliability and access delay requirements, and for this reason,
erasure codes with different strengths need to be utilized to achieve the best
storage efficiency. At the same time, in such large scale distributed storage
systems, nodes fail on a regular basis, and the contents stored on them need to
be regenerated and stored on other healthy nodes, the efficiency of which is an
important factor affecting the overall quality of service. In this work, we
formulate the problem of multilevel diversity coding with regeneration to
address these considerations, for which the storage vs. repair-bandwidth
tradeoff is investigated. We show that the extreme point on this tradeoff
corresponding to the minimum possible storage can be achieved by a simple
coding scheme, where contents with different reliability requirements are
encoded separately with individual regenerating codes without any mixing. On
the other hand, we establish the complete storage-repair-bandwidth tradeoff for
the case of four storage nodes, which reveals that codes mixing different
contents can strictly improve this tradeoff over the separate coding solution.
