Funnily enough, i wasn't aware of ObjectiveFS - i guess it's because i can't find a research paper for it. HopsFS on S3 is similar to ADLS on Azure (built on Azure block storage). Internally, ADLS and HopsFS are different - HopsFS has a scaleout consistent metadata layer with a CDC API, while ADLS doesn't. But ADLS-v2 is also very good.