RAID and snapshots

source/talk.tex

@@ -11,7 +11,7 @@
 \def\UrlBreaks{\do\/\do-}
 
 %Information to be included in the title page:
-\title{Backup and (possibly) Restore}
+\title{Backup and (hopefully) Restore}
 \author{Andrea Gussoni}
 \institute{P.O.u.L.}
 \date{23 Marzo 2017}
@@ -27,7 +27,7 @@
   Bad things can happen and do happen:
   \begin{itemize}
     \item You may drop your computer accidentally.
-    \item The disk may be damaged by vibrations during the daily train commute.
+    \item The disk may be damaged by vibrations during the daily commute.
     \item The computer where you keep the unique copy of your thesis
     may be stolen.
     \item Or after some time it may simply age and stop operating.
@@ -264,18 +264,70 @@
   %\pause
   %\footnotesize{I don't want to put shame on GitLab for this incident, but only to use it as a case study.\\ In fact I think that the incident has been managed really well by the GitLab Team.\\
   %Instead of starting blaming each other and finding silly excuses as usually happens in cases like this, they have been really open from the beginning about the problem and put as a priority the restore of the functionality of the service.}
+\end{frame}
 
+\begin{frame}
+  \frametitle{Before the Backup}
+  A different approach to data protection is to use RAID (\textit{Redundant Array of Independent Disks}).\\
+  \pause
+  In general what we try to obtain with RAID is:
+  \begin{itemize}
+    \item Survival of the system if a disk failure happen.
+    \item In certain conditions we can achieve higher performances compared to the single disk case.
+  \end{itemize}
+  \footnotetext{For further informations you can visit \url{https://www.digitalocean.com/community/tutorials/an-introduction-to-raid-terminology-and-concepts}}
 \end{frame}
 
 \begin{frame}
-    \frametitle{References}
-    \begin{itemize}
-        \item \url{https://wiki.archlinux.org/index.php/Full_system_backup_with_rsync}
-        \item \url{https://wiki.archlinux.org/index.php/Duplicity}
-        \item \url{http://duplicity.nongnu.org/}
-        \item \url{https://www.digitalocean.com/community/tutorials/how-to-use-duplicity-with-gpg-to-securely-automate-backups-on-ubuntu}
-        \item \url{https://github.com/zertrin/duplicity-backup.sh}
-    \end{itemize}
+  \frametitle{RAID Configurations}
+  \begin{figure}
+    \centering
+    \includesvg[width = 75pt]{RAID_0}
+    \includesvg[width = 75pt]{RAID_1}\\
+    \includesvg[width = 150pt]{RAID_5}
+  \end{figure}
+\end{frame}
+
+\begin{frame}
+  \frametitle{Problems}
+  RAID can help in the event of a disk failure, but it doesn't protect us against \textbf{Silent Data Corruption}\\\pause
+  To address this problem new generation filesystems like ZFS or Btrfs have been created. Classical features that we can find in this kind of fylesistems are:
+  \begin{itemize}
+      \item CopyOnWrite
+      \item Deduplication
+      \item Data \& Metadata checksums
+      \item Integrated RAID
+      \item Volume Management
+      \item Snapshots
+  \end{itemize}
+\end{frame}
+
+\begin{frame}
+  \frametitle{Snapshots}
+  \begin{itemize}
+    \item Snapshots can be particularly useful because they allow us to obtain an (almost) instant snapshot of a volume that we can restore later, archive somewhere etc.\\\pause
+    \item So we can use them in order to do some potential risky modifications on a system and restore the previous state with a little effort.\\\pause
+    \item Remember that having a separate \textit{classical} backup is always useful, in particular for important data of our applications.\pause
+    \item RAID is not a backup.
+  \end{itemize}
+\end{frame}
+
+\begin{frame}
+  \frametitle{References}
+  \begin{itemize}
+    \item \url{https://wiki.archlinux.org/index.php/Full_system_backup_with_rsync}
+    \item \url{https://wiki.archlinux.org/index.php/Duplicity}
+    \item \url{http://duplicity.nongnu.org/}
+    \item \url{https://www.digitalocean.com/community/tutorials/how-to-use-duplicity-with-gpg-to-securely-automate-backups-on-ubuntu}
+    \item \url{https://github.com/zertrin/duplicity-backup.sh}
+  \end{itemize}
+\end{frame}
+
+\begin{frame}
+  \frametitle{Special Thanks}
+  I used as reference and starting point for this presentation the material of the previous editions of the course.\\
+  Special thanks to \textit{Valeria Mazzola}\footnote{\url{https://slides.poul.org/2016/corsi-linux-avanzati/Backup_and_Restore.pdf}} and \textit{Federico Amedeo Izzo}\footnote{\url{https://filesystem.izzo.ovh/}} for the slides of the two previous edition of this talk.
+
 \end{frame}
 
 \begin{frame}