\section{Volumes and Volume Groups}

\begin{frame}
   {Volumes and Volume Groups}
   \begin{multicols}{2}
      \begin{figure}[H]
         \includegraphics[height=2.2in]{IMAGES/LVM_Components}
         \caption{LVM components}
      \end{figure}

      \begin{itemize}
         \item Devices are converted to physical volumes
         \item Multiple physical volumes are grouped into
         volume groups
         \begin{itemize}
            \item Volume groups divided into extents
            \item Extent size can be defined (4 MB default)
         \end{itemize}
         \item Logical volumes allocated from volume groups
         \begin{itemize}
            \item Can be defined by size or number of
            extents
            \item Filesystems are built on logical volumes
            \item Can be named anything
         \end{itemize}
      \end{itemize}

   \end{multicols}
\end{frame}

\cprotect\note{
   Partitions are converted to physical volumes and
   multiple physical volumes are grouped into volume
   groups; there can be more than one volume group on the
   system.
   Space in the volume group is divided into
   \textbf{extents}; these are 4 MB in size by default,
   but the size can easily be changed when being
   allocated.

   There are a number of command line utilities used to
   create and manipulate volume groups, whose name always
   start with \textbf{vg} including:
   \begin{itemize}
      \item \textbf{vgcreate}: Creates volume groups.
      \item \textbf{vgextend}: Adds to volume groups.
      \item \textbf{vgreduce}: Shrinks volume groups.
   \end{itemize}

   Utilities that manipulate what physical partitions
   enter or leave volume groups start with \textbf{pv} and
   include:

   \begin{itemize}
      \item
      \textbf{pvcreate}: Converts a partition to a physical
      volume.
      \item
      \textbf{pvdisplay}: Shows the physical volumes being used.
      \item
      \textbf{pvmove}: Moves the data from one physical
      volume within the volume group to others; this might be
      required if a disk or partition is being removed for
      some reason.  It would then be followed by:
      \item
      \textbf{pvremove}: Remove a partition from a physical
      volume.
   \end{itemize}

   Typing \texttt{man lvm} will give a full list of \textbf{LVM}
   utilities.
}



