DAOS operates over two, closely integrated planes, Control and Data. The Data plane handles the heavy lifting transport operations while the Control plane orchestrates process and storage management, facilitating the operation of the Data plane.
The DAOS Control Plane is written in Go and runs as the DAOS Server
(daos_server) process. It is tasked with network and storage hardware
provisioning and allocation in addition to instantiation and management of the
DAOS Data Plane (Engine) processes that run on the same host.
The control directory contains a "cmd" subdirectory for server, agent, ddb, and
dmg applications. These applications import the control API
(src/control/lib/control) or server packages along with peripheral shared
packages common, drpc, fault, logging, and security where necessary to provide
the given features.
Specific library packages can be found in lib/ which provide access to native storage libraries through language bindings, e.g. lib/spdk or specific formatting capabilities e.g., lib/hostlist or lib/txtfmt.
The events package provides the golang component of the RAS framework for receipt of events over dRPC from the DAOS Engine and forwarding of management service actionable events to the MS leader.
The pbin package provides a framework for forwarding of requests to be executed
by the privileged binary daos_server_helper on behalf of daos_server.
The provider package contains interface shims to the external environment, initially just to the Linux operating system.
The system package encapsulates the concept of the DAOS system, and its associated membership.
Please refer to package-specific README's.