We are experimenting with Bluemix cloud foundry. In our experiment we are horizontally scaling and doing zero-down-time deploy's.
According to the documentation in Mendix 7 it is no longer needed to store sessions in an external store. (https://github.com/mendix/cf-mendix-buildpack#configuring-clustering-for-mendix-7)
Though our experiance is that we loose our session during a zero-down-time deploy. Is that expected?