We have a database running on a linux box (progress database) currently using a G400 with sas drives. We've added a dell/emc all flash unity but the response times for the database writes are more than double for the unity! The database vendors's saying they use direct writes and thats the issue - but I can't see how that is an issue on a storage box , internal storage maybe. And I can't see and HOM/SOM that would allow it. So I'm trying to find out what happens in both boxes when they receive a write request, does anyone know for the G400 -eg write to cache, mirrored, acknowledgement sent , write to disk etc