\chapter{Introduction}
Welcome to Skylable \SX, a complete private cloud framework. With Skylable \SX
you can create flexible, reliable and secure storage solutions, which can
be accessed from all popular platforms.

\section{\ifpdf\texorpdfstring{\SX Features}{SX Features}\else{\SX Features}\fi}
This software has been designed and built with usability in mind. Some
of the great features of Skylable \SX include:
\begin{itemize}
    \item \textbf{Fast and lightweight protocol}\\
    Never transfer the same data twice. The \SX protocol transfers only the
    differences between the local copy of a file and the data already stored
    in the cluster. Additionally, it transfers data to/from all SX nodes in
    parallel to maximize speed.

    \item \textbf{Replication}\\
    Choose how many times you want your data to be replicated. You can set
    different levels of replica for different data and find the perfect
    balance between reliability and efficiency.

    \item \textbf{Rack Awareness}\\
    Ensure data gets replicated across different racks or regions by grouping
    nodes into zones.

    \item \textbf{Deduplication}\\
    If you upload 10 copies of the same data, that data takes the same
    space as 1 copy. If you upload 10 files, which only differ in a few bytes,
    just the differences between the files will take up additional space and
    the rest will be deduplicated.

    \item \textbf{Encryption}\\
    Client-side encryption with AES256, HTTPS communication, and all the
    security best practices to keep your data safe.

    \item \textbf{Revisions and undelete}\\
    \SX can optionally keep multiple revisions of your files and allow you to
    go back in time to previous versions of your files. You can also restore
    a file that has been accidentally deleted.

    \item \textbf{S3 Support}\\
    Need a drop-in replacement for S3? Install \SX together with LibreS3 and
    change a single setting in your S3 clients and tools: that's all you need
    to do to switch to Skylable.

    \item \textbf{Mobile and Desktop clients}\\
    Keep your files synchronized across all your devices with SXDrive: available
    for Windows/MacOSX/Linux on desktop and iOS/Android on mobile.
\end{itemize}

\section{Skylable ecosystem}
This manual covers the open-source Skylable \SX software for UNIX platforms.
\SX is used to create data clusters and forms the base for the Skylable
platform, which consists of multiple components as shown on \ifpdf\fref{fig:components}\else\ref{fig:components}.\fi
\begin{figure}
    \centering
    \input{tikz_components.tex}
    \caption{Skylable cloud ecosystem}
    \label{fig:components}
\end{figure}
With Skylable \SX one can build a cloud consisting of many nodes, which can
be accessed in different ways and from multiple platforms. The client
applications include command-line tools, which are part of the Skylable \SX
itself, as well as desktop and mobile apps.

The command line tools shipped with Skylable \SX provide a typical UNIX
experience and together with external tools and scripts can be used to
automate various processes, such as backups.

\textbf{\SX Drive for Linux, Windows and OS X} keeps remote data synchronized with
a local directory. The synchronization works both ways, and the latest data
is always available on the local machine and in the cloud.

\textbf{\SX Drive for Android and iOS} provides an instant access to the cloud from
mobile devices. One can upload or download any documents or photos and keep
favourite files automatically updated.

\textbf{\SX Web} provides a web interface to the cloud. Users can access all their
data right from web browsers. \SX Web additionally provides an easy way to
share files with other people.

\textbf{\SX Console} provides a web-based management console for the cluster. The
cluster administrators can perform all regular operations right from a browser.
\SX Console makes it easy to manage users, volumes, monitor health and status
of the cluster.

Finally, with \textbf{LibreS3}, the Skylable cloud becomes available to clients
compatible with the S3 protocol. LibreS3 implements a large subset of the
S3 API and translates it to the \SX protocol. It makes possible to use
existing solutions such as s3cmd or DragonDisk with Skylable \SX.
