Hi guys!
I know there a lot james versions but i have problem - i test Cassandra in disturbed-app and i like it but for standalone server its not that good, there also postgres-app and it have some problems personally for me - if use with s3 there no good way to make correct sync backup, and even with blobs in postgresql things not getting much better because vacuum really pretty hard for ram/cpu and disk (on big data hell for hdd). Yes there is jpa-app with mysql which for me best database but i found Xodus and it fits really well for mail server nature - its not sql strict, more like mongodb, but full acid and it battle tested db by jet brains (yes it is sunset state but for me its even better - feature complete) https://github.com/prosgarz35/xodus-app
