I did a project with Monash university who were using Versity on their storage to handle multi tiers storage on their 12PB cluster, with glacier like capabilities on tape storage with a robot picking up data on their tape backup and a hot storage tier for better access performance, lifecycle rules to move data from hot storage to cold, etc.... The underlying storage was all Versity and they had Filestash working on top, effectively we did some custom plugins so you could recall the data on their own selfhosted glacier while using it through the frontend so their user had a Dropbox like experience. Depending on what you want to do they can be very much complimentary