From 8cce903a981c004502d1fdf29a650fc58f72042d Mon Sep 17 00:00:00 2001
From: mjkwiatkowski <mati.rewa@gmail.com>
Date: Mon, 20 Jul 2026 12:43:25 +0200
Subject: git amend

---
 content/background.tex | 53 +++++++++++++++++++++++++-------------------------
 1 file changed, 27 insertions(+), 26 deletions(-)

(limited to 'content/background.tex')

diff --git a/content/background.tex b/content/background.tex
index 97dc6aa..68ce6a2 100644
--- a/content/background.tex
+++ b/content/background.tex
@@ -47,31 +47,7 @@ Making sure that all the parts of the datacenter work together is a tough task.
 What drives datacenter complexity even further is that sophisticated systems are not merely a sum of their parts~\cite{Wikipedia:article/Systems_Thinking}.
 The combination of the above factors makes datacenter management a difficult, non-trivial challenge.
 
-\subsection{Datacenter Simulation}\label{sss:simulation}
-\input{sources/simulator_comparison.tex}
-
-Efficient and timely datacenter management is a difficult challenge, because datacenters are extremely complex facilities.
-They require deep understanding to operate properly.
-However, running real-world experiments is costly in both time and resources.
-Additionally, experimentation \emph{in situ} is unsustainable and difficult to reproduce.
-Alternatives to real-world experiments include simulation and mathematical analysis.
-Because mathematical analysis is not scalable to modern datacenters~\cite{DBLP:conf/ccgrid/MastenbroekAJLB21}, in this project we only consider simulation as a foundation for the \gls{dcdt}.
-%To help datacenter operators, the scientific community proposes to simulate datacenters to make more informed decisions.
-
-Simulation empowers better design, testing and management of datacenters~\cite{DBLP:conf/ccgrid/MastenbroekAJLB21}.
-A well-designed datacenter simulator can estimate a months-long workload in a few minutes or hours.
-To simulate is to ``imitate of real-world process or system over time, enabling the study of, and experimentation with the internal interactions of complex systems''~\cite{DBLP:books/daglib/0034857}
-In this project we only consider  \emph{discrete-event simulation}.
-Discrete-event simulation represents system operations as a sequence of events over time, with an assumption that no changes occur between the events.
-Due to the scale and complexity of datacenters, most simulators use discrete-event simulation~\cite{DBLP:conf/ccgrid/MastenbroekAJLB21}.
-There exist many datacenter simulation tools, for example DGSim~\cite{DBLP:conf/europar/IosupSE08}, CloudSim~\cite{DBLP:journals/spe/CalheirosRBRB11}, SimGrid~\cite{DBLP:journals/corr/CasanovaGLQS13}, iCanCloud~\cite{DBLP:journals/grid/NunezVCCCL12}, GroudSim~\cite{DBLP:conf/europar/OstermannPPF10} and OpenDC~\cite{DBLP:conf/ccgrid/MastenbroekAJLB21}.
-See \Cref{tab:datacenter_simulator_comparison} for a comparison of selected datacenter simulators, combined by Mastenbroek \etal~\cite{DBLP:conf/ccgrid/MastenbroekAJLB21}.
-In order to narrow the scope of the project, we only consider {OpenDC} as a simulator for the digital twin design.
-We decided to use {OpenDC}, because we find it important for a simulator to model hardware failures well.
-\emph{Failure models} are a carefully calibrated, advanced feature of {OpenDC}.
-Further details about {OpenDC} can be referred to in the linked literature \cite{DBLP:conf/ccgrid/MastenbroekAJLB21}.
-
-\subsection{Compute Failures}\label{sss:failures}
+\section{Compute Failures}\label{sss:failures}
 A failure is defined as ``an event that makes a system fail to operate according to its specifications``~\cite{DBLP:journals/jpdc/JavadiKIE13}.
 A simple example of a failure is when an old hard drive stops working.
 Data on the disk is lost, and services running on the respective server are disrupted.
@@ -99,10 +75,35 @@ A failure trace is defined by an interval, duration, and intensity of several fa
 In summary OpenDC enables experimentation with failures that enables insights that are not provided by other state-of-the-art software.
 However, the fidelity of failure modeling inside a datacenter simulation is still insufficient to predict in failures in real-time, as they happen in a physical datacenter.
 Since a datacenter simulator is quite different from a digital twin, we cannot use the same computation methods from simulation to predict real-time failures.
+\section{Datacenter Simulation}\label{sss:simulation}
+\input{sources/simulator_comparison.tex}
+
+Efficient and timely datacenter management is a difficult challenge, because datacenters are extremely complex facilities.
+They require deep understanding to operate properly.
+However, running real-world experiments is costly in both time and resources.
+Additionally, experimentation \emph{in situ} is unsustainable and difficult to reproduce.
+Alternatives to real-world experiments include simulation and mathematical analysis.
+Because mathematical analysis is not scalable to modern datacenters~\cite{DBLP:conf/ccgrid/MastenbroekAJLB21}, in this project we only consider simulation as a foundation for the \gls{dcdt}.
+%To help datacenter operators, the scientific community proposes to simulate datacenters to make more informed decisions.
+
+Simulation empowers better design, testing and management of datacenters~\cite{DBLP:conf/ccgrid/MastenbroekAJLB21}.
+A well-designed datacenter simulator can estimate a months-long workload in a few minutes or hours.
+To simulate is to ``imitate of real-world process or system over time, enabling the study of, and experimentation with the internal interactions of complex systems''~\cite{DBLP:books/daglib/0034857}
+In this project we only consider  \emph{discrete-event simulation}.
+Discrete-event simulation represents system operations as a sequence of events over time, with an assumption that no changes occur between the events.
+Due to the scale and complexity of datacenters, most simulators use discrete-event simulation~\cite{DBLP:conf/ccgrid/MastenbroekAJLB21}.
+There exist many datacenter simulation tools, for example DGSim~\cite{DBLP:conf/europar/IosupSE08}, CloudSim~\cite{DBLP:journals/spe/CalheirosRBRB11}, SimGrid~\cite{DBLP:journals/corr/CasanovaGLQS13}, iCanCloud~\cite{DBLP:journals/grid/NunezVCCCL12}, GroudSim~\cite{DBLP:conf/europar/OstermannPPF10} and OpenDC~\cite{DBLP:conf/ccgrid/MastenbroekAJLB21}.
+See \Cref{tab:datacenter_simulator_comparison} for a comparison of selected datacenter simulators, combined by Mastenbroek \etal~\cite{DBLP:conf/ccgrid/MastenbroekAJLB21}.
+In order to narrow the scope of the project, we only consider {OpenDC} as a simulator for the digital twin design.
+We decided to use {OpenDC}, because we find it important for a simulator to model hardware failures well.
+\emph{Failure models} are a carefully calibrated, advanced feature of {OpenDC}.
+Further details about {OpenDC} can be referred to in the linked literature \cite{DBLP:conf/ccgrid/MastenbroekAJLB21}.
+
 \begin{figure}[t]
 	\centering
 	\includegraphics[width=0.95\linewidth]{images/five_dimensional_dt.png}
-	\caption[A basic framework for the \gls{dt}.]{A basic framework for the \gls{dt}. Four core elements of a \gls{dt} are defined: The physical entity (\myCircled{1}) and the simulated virtual twin (\myCircled{2}). A service for out-of-band data analytics (\myCircled{3}) and a persistent storage of historical data (\myCircled{4}) are crucial to the \gls{dt} because they are necessary to gain meaningful monitoring insights. Adapted from Tao \etal ~\cite{DBLP:conf/cirp/TAO2018169}.}
+	\caption[A basic framework for the Digital Twin.]{A basic framework for the \gls{dt}. Four core elements of a \gls{dt} are defined: The physical entity (\myCircled{1}) and the simulated virtual twin (\myCircled{2}). A service for out-of-band data analytics (\myCircled{3}) and a persistent storage of historical data (\myCircled{4}) are crucial to the \gls{dt} because they are necessary to gain meaningful monitoring insights. Adapted from Tao \etal ~\cite{DBLP:conf/cirp/TAO2018169}.}
+
 	%Fei Tao is a renowned figure with over 62k citations. He is a figure of authority on digital twins.%
 	\label{fig:five_dimensional_dt}
 \end{figure}
-- 
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