Synnefo » snf-ganeti

          <arg>--file-storage-dir <replaceable>dir_path</replaceable></arg>

          <arg>--file-driver <group choice="req">

              <arg>loop</arg>

              <arg>blktap</arg>

            </group></arg>

          <sbr>

              <arg>file</arg>

              <term>file</term>

              <listitem>

                <para>Disk devices will be regular files.</para>

              </listitem>

            </varlistentry>

            <varlistentry>

          The <option>--file-storage-dir</option> specifies the relative path

          under the cluster-wide file storage directory to store file-based

          disks. It is useful for having different subdirectories for

          different instances. The full path of the directory where the disk

          files are stored will consist of cluster-wide file storage directory

          + optional subdirectory + instance name. Example:

          /srv/ganeti/file-storage/mysubdir/instance1.example.com. This option

          is only relevant for instances using the file storage backend.

        </para>

        <para>

          The <option>--file-driver</option> specifies the driver to use for

          file-based disks. Note that currently these drivers work with the

          xen hypervisor only. This option is only relevant for instances using

          the file storage backend. The available choices are:

          <variablelist>

            <varlistentry>

              <term>loop</term>

              <listitem>

                <para>Kernel loopback driver.</para>

              </listitem>

            </varlistentry>

            <varlistentry>

              <term>blktap</term>

              <listitem>

                <para>blktap driver.</para>

              </listitem>

            </varlistentry>

          <variablelist>

        </para>

        <para>

          The loop driver uses loopback devices to access the filesystem

          within the file. However, running I/O intensive applications

          in your instance using the loop driver might result in slowdowns.

          Furthermore, if you use the loopback driver consider increasing

          the maximum amount of loopback devices (on most systems it's 8)

          using the max_loop param.

        </para>

        <para>

          In order to be able to use the blktap driver you should check

          if the 'blktapctrl' user space disk agent is running (usually

          automatically started via xend). This user-level disk I/O

          interface has the advantage of better performance. Especially

          if you use a network file system (e.g. NFS) to store your instances

          this is the recommended choice.

        </para> 

        <para>

# gnt-instance add -t file -s 30g -m 512 -o debian-etch \

  -n node1.example.com --file-storage-dir=mysubdir instance1.example.com