\begin{lstlisting}[caption=The Redis and PostgreSQL schema (\texttt{schema.proto} file). All the large volume data packets that travel within the system follow this format (\ie \myCircled{1} through \myCircled{6}). The communication of small datapackets takes place using the \gls{http} protocol., label={lst:protobuf-schema}] syntax = "proto3"; package proto; option java_package = "org.opendc.common"; option java_outer_classname = "ProtobufMetrics"; message ProtoExport { string timestamp = 1; string host_id = 2; int32 tasksactive = 3; double cpuutilization = 4; double energyusage = 5; double uptime = 6; double downtime = 7; }\end{lstlisting}