After upgrading from 2.1.0 to 2.1.1 firmware the Drobo S 2nd Gen. was not detected in Windows 7 64 Bit anymore using IDE mode on eSata. In BIOS it was recognized as before.
Using USB 3.0 ports the Drobo S did not go into sleep mode together with the PC, it did only when the PC was shut down.
After a request to support I went back to firmware 2.1.0 and the Drobo S works again in IDE mode on an eSata port as before.
Just a note to everyone: I was told going back to 2.1.0 would delete all data was just not true - ALL DATA where still on the Drobo S !
I will be very careful in updating firmware in the future !!