From 0018fdbff007f689e9cd7d877d72db4fd308b65f Mon Sep 17 00:00:00 2001 From: mjkwiatkowski Date: Wed, 15 Jul 2026 14:35:04 +0200 Subject: feat: addressed all the feedback from Dante for background --- content/background.tex | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) (limited to 'content') diff --git a/content/background.tex b/content/background.tex index 8349bcf..17d7d47 100644 --- a/content/background.tex +++ b/content/background.tex @@ -73,15 +73,23 @@ Further details about {OpenDC} can be referred to in the linked literature \cite \subsection{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}. -We distinguish 2 failure types: \begin{enumerate*}[label=(\arabic*)] - \item software failures - \item hardware failures. -\end{enumerate*} -For example, a hypervisor crash a software failure. -Each \gls{vm} within the crashed hypervisor is killed as a result. -An example of a hardware failure is a host crash, where a single server stops working (\eg as a result of a disk fault, or faulty power supply cable). -Hardware and software failures in datacenters result in service downtime, missed \gls{sla} and user inconvenience~\cite{DBLP:conf/acsos/TalluriOVTI21, 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. +In reality, problems with the power supply account for most failures (54\%). +The runner-ups are problems with cooling (13\%), and \gls{it}/software (12\%)~\cite{DBLP:report/AnnualOutageAnalysis2025}. +Power related failures may stem from software/firmware issues, battery degradation, overheating, power generator failure, mechanical problems, faulty control logic \etc~\cite{DBLP:report/AnnualOutageAnalysis2025}. + +Failure-caused outages are costly. +According to the Uptime Institute, 20\% of all outages cost more than 1 million +USD\$~\cite{DBLP:report/AnnualOutageAnalysis2025}. +Moreover, failures in datacenters result in service downtime, missed \gls{sla} and user inconvenience~\cite{DBLP:conf/acsos/TalluriOVTI21, DBLP:journals/jpdc/JavadiKIE13}. +Industries that rely on 24 hour access suffer the most from datacenter outages. +The impact of failures on medical informatics, nuclear power-plants, banks and financial institutions, airlines, and e-commerce is the most severe~\cite{Wikipedia:article/Downtime}. +Because of this, it is important to prevent failures. + OpenDC uses the notion of a \emph{failure model} to simulate failures, alongside \emph{failure traces}. +In OpenDC, a failure constitutes a full host crash, regardless of whether the cause of the failure is a hardware of software problem. +A result of a failure in OpenDC, all tasks running on the given host are killed, and need to be rescheduled. A failure model consists of two statistical distributions: \begin{enumerate*}[label=(\arabic*)] \item to model service unavailability -- cgit v1.2.3