  Hyper-converged cloud refers to an architecture that an operator runs compute
and storage services on the same set of physical servers. Although the
hyper-converged design comes with a number of benefits, it makes crucial
operational tasks, such as capacity planning and cost analysis, fairly
complicated. The problem becomes more onerous if we consider a complex
distributed system, such as Ceph, for the cloud with the proliferation of SSD
drives. In this paper, we aim to answer some of these questions based on
comprehensive microbenchmarks, and consequently better understand the behavior
of Ceph in a hyper-converged cloud with all-flash storage. We reported our
findings based on the study, devised a cost model and compared the cost of
hyper-converged architecture with dedicated storage architecture. Additionally
we summarized our experience based on the interactions with many teams at AT&T
in the past couple of years.
