Hello, we are currently managing access permissions through classical user-group-others permissions on a multi-petabyte directory tree with partially very deep and broad directories. Projects are represented by directory trees and mapped through GIDs. Lately we had lots of "singular" permission request (one single user needs access to a single dataset but should not be able to see all other datasets belonging to the same project). We realized, that the UGO model doesn't scale and is becoming more and more unmanageable. Can you recommend tools/mechanisms/technologies to overcome the drawbacks of the UGO model? We are thinking about some purely ACL based mechanism (but are open to other ideas). All filesystems in question are mounted via NFSv4 and the clients are (almost) completely CentOS 7.x hsots. Ideally the tool would have some web UI and some kind of (REST)API which allows us to modify permissions from our inhouse data management application (which does /not/ manage permissions, just the structure of the data). Additionally it should be able to visualize/report permissions in directory. I wasn't very successful in googling possible candidates, hence the question to the list. Cheers frank