LaTeX Forum

\documentclass[tikz, border=10pt]{standalone}
\usetikzlibrary{positioning}
\usetikzlibrary{calc}
\usetikzlibrary{arrows.meta}

\tikzset{
	nodes={font=\sffamily},
	blockrand/.style={
		draw, 
		rounded corners, 
		thick
	},
	block/.style={
		blockrand, 
		minimum height=3em, 
		minimum width=9em
	},
	breit/.style={
		blockrand, 
		minimum height=6em, 
		minimum width=#1
	}, 
	pfeil/.style={
		-{Stealth[length=2mm,width=3mm]}, 
		shorten >=1pt, 
		rounded corners, 
		ultra thick
	}
}

\begin{document}
\begin{tikzpicture}
\node[block](c1){Client 1};
\node[block, right=of c1]     (c2) {Client 2}; 
\node[block, right=of c2]     (s1) {Server 1}; 
\node[block, right=of s1]     (s2) {Server 2};
\node[block, below=5cm of s2] (d)  {Database};

\path let \p1=(c1.west), \p2=(s2.east) in 
	node[breit={\x2-\x1}, below=of c1.south west, anchor=north west] (os) {}
	(os.south west) node[above right,outer sep=1em] {OS};
    
\draw[pfeil] (c1.south) -- ++ (0,-5em) -| (s1.south);
\draw[pfeil] (c2.south) -- ++ (0,-4em) -| ([xshift=-2em]s1.south);
\draw[pfeil] ([xshift=2em]s1.south) -- ++ (0,-6em) -| ([xshift=-1.5em]s2.south);
\draw[pfeil] ([xshift=1.5em]s2.south) -- ([xshift=1.5em]d.north);

\path (os) -- coordinate (halberweg) (d);
\draw[dashed]
	([xshift=-2.5cm]current bounding box.west|-halberweg) -- 
	node [pos=.03, above=1em] {SW}
	node [pos=.03, below=1em] {HW}
	(current bounding box.east|-halberweg)
;
\end{tikzpicture}
\end{document}

\documentclass{article}
\usepackage[british]{babel}
\usepackage{tikz}
\usetikzlibrary{positioning}
\usetikzlibrary{calc}

\tikzset{ 
  block/.style={minimum height=3em, minimum width=9em, draw=black},
  breit/.style={minimum height=6em, 
  minimum width=#1,
  draw=black}, 
  pfeil/.style={->, shorten >=1pt, thick}}

\begin{document}

 \begin{tikzpicture}
    \node[block](c1){Client 1};
    \node[block, right=of c1] (c2) {Client 2}; 
    \node[block, right=of c2] (s1) {Server 2}; 
    \node[block, right=of s1] (s2) {Server 2};
    \path let \p1=(c1.west), \p2=(s2.east) in 
      node[breit={\x2-\x1}, below=of c1.south west, anchor=north west] (os) {}
      (os.south west) node[above right,outer sep=1em] {OS};
    
    \draw[pfeil] (c1.south) |- (3,-2.3) -|  (s1.south);
    \draw[pfeil] (c2.south) |- (5,-2) -|  ([xshift=1em]s1.south west);
    
   \node[block, below=5cm of s2](d){Database};
  \end{tikzpicture}

\end{document}

\documentclass{article}
\usepackage[british]{babel}
\usepackage{tikz}
\usetikzlibrary{positioning}

\tikzset{ 
  block/.style={minimum height=3em, minimum width=9em, draw=black},
  breit/.style={minimum height=6em, minimum width=40em, draw=black}, 
  pfeil/.style={->, shorten >=1pt, thick}}

\begin{document}

 \begin{tikzpicture} 
    \node[block](c1){Client 1};
    \node[block, right=of c1] (c2) {Client 2}; 
    \node[block, right=of c2] (s1) {Server 2}; 
    \node[block, right=of s1] (s2) {Server 2};
    \node[breit, below=of c2, xshift=6em] (os) {OS};
    
    \draw[pfeil] (c1.south) |- (3,-2.3) -|  (s1.south);
    \draw[pfeil] (c2.south) |- (5,-2) -|  ([xshift=1em]s1.south west);
    
   \node[block, below=5cm of s2](d){Database};
  \end{tikzpicture}

\end{document}

\documentclass{article}
\usepackage[british]{babel}
\usepackage{tikz}
\usetikzlibrary{positioning}

\begin{document}

 \begin{tikzpicture}[ 
  nodes=draw,
  block/.style={minimum height=6em, minimum width=9em} ] 
    \node[block](c1){Client 1};
    \node[block, right=of c1] (c2) {Client 2}; 
    \node[block, right=of c2] (s1) {Server 2}; 
    \node[block, right=of s1] (s2) {Server 2}; 
%    \node[block](d){Database};
  \end{tikzpicture}

\end{document}

\documentclass[tikz, border=5pt]{standalone}
\usepackage[british]{babel}

\usetikzlibrary{positioning}

\begin{document}
\begin{tikzpicture}[ 
	nodes=draw,
	block/.style={minimum height=6em, minimum width=9em}
] 
\node[block](c1){Client 1};
\node[block, right=of c1](c2){Client 2}; 
% \node[block](s1){Server 2}; 
% \node[block](s2){Server 2}; 
% \node[block](s2){Database};
\end{tikzpicture}
\end{document}

\documentclass{article}
\usepackage[british]{babel}
\usepackage{tikz}


\begin{document}

 \begin{tikzpicture}[ 
  nodes=draw,
  block/.style={minimum height=6em, minimum width=9em} ] 
    \node[block](c1){Client 1};
    \node[block](c2){Client 2}; 
    \node[block](s1){Server 2}; 
    \node[block](s2){Server 2}; 
    \node[block](s2){Database};
  \end{tikzpicture}

\end{document}