Never use \\
at the end of a paragraph and do not change the \parskip
manually (see https://tex.stackexchange.com/a/14565/43317).
You could load package parskip
\documentclass{article}
\usepackage{parskip}
\begin{document}
\section{Introduction}
In a distributed database system, data is replicate of the most important advantages of replication is that it masks and tolerates failures in the network gracefully and increases availability.
In case of multiple access a problem that must be solved while using replication is about maintaining the a generalization of the majority consensus method presented in
This protocol can be viewed as specialized version of ring and tree protocol.
As compared to other protocols, wheel protocol can be used for arbitrary number of nodes.
\end{document}

Or you could use a KOMA-Script class with option parskip=full-
:
\documentclass[parskip=full-]{scrartcl}
\begin{document}
\section{Introduction}
In a distributed database system, data is replicate of the most important advantages of replication is that it masks and tolerates failures in the network gracefully and increases availability.
In case of multiple access a problem that must be solved while using replication is about maintaining the a generalization of the majority consensus method presented in
This protocol can be viewed as specialized version of ring and tree protocol.
As compared to other protocols, wheel protocol can be used for arbitrary number of nodes.
\end{document}
See the KOMA-Script documentation to find more possible values for option parskip
.
If you want to use a parskip that differs from half
or full
you can use the command \setparsizes{<parindent>}{<parskip>}{<horizontal white space at the end of a paragraph>}
.
Example with a parskip
of 2\baselineskip
:
\documentclass{scrartcl}
\setparsizes{0pt}{2\baselineskip}{0pt plus 1fill}
\begin{document}
\section{Introduction}
In a distributed database system, data is replicate of the most important advantages of replication is that it masks and tolerates failures in the network gracefully and increases availability.
In case of multiple access a problem that must be solved while using replication is about maintaining the a generalization of the majority consensus method presented in
This protocol can be viewed as specialized version of ring and tree protocol.
As compared to other protocols, wheel protocol can be used for arbitrary number of nodes.
\end{document}
If parskip
should depend on the fontsize you can try option parskip=relative
additionally:
\documentclass[parskip=full-,parskip=relative]{scrartcl}
\begin{document}
\section{Introduction}
In a distributed database system, data is replicate of the most important advantages of replication is that it masks and tolerates failures in the network gracefully and increases availability.
In case of multiple access a problem that must be solved while using replication is about maintaining the a generalization of the majority consensus method presented in
This protocol can be viewed as specialized version of ring and tree protocol.
As compared to other protocols, wheel protocol can be used for arbitrary number of nodes.
\rule{\linewidth}{.4pt}
\tiny
In a distributed database system, data is replicate of the most important advantages of replication is that it masks and tolerates failures in the network gracefully and increases availability.
In case of multiple access a problem that must be solved while using replication is about maintaining the a generalization of the majority consensus method presented in
This protocol can be viewed as specialized version of ring and tree protocol.
As compared to other protocols, wheel protocol can be used for arbitrary number of nodes.
\end{document}

\\
it generates underfull hbox warnings and the warnings shouldn't be ignored it makes very poor output that does entirely the wrong thing at page breaks (and other places)