This would not necessarily affect back end development as you would still want high availability for the application by using an active-active setup across two

This would not necessarily affect back end development as you would still want high availability for the application by using an active-active setup across two availability zones in EC2. With regard to your question on data structures, yes - they would have to change. MySQL and most other databases use b-trees since they were meant to live on disk. Just running MySQL on memsistor-backed storage would result in a considerable waste of CPU and storage capacity (b-trees are not very compact). Running a database like MemSQL on memsistors would make the most sense since it uses data structures meant for DRAM.