RHEL 6 Virtualization - Chapter 28. Miscellaneous storage topics

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Chapter 28. Miscellaneous storage topics

28.1. Creating a virtualized floppy disk controller
28.2. Configuring persistent storage in Red Hat Enterprise Linux 6
28.3. Accessing data from a guest disk image

28.1. Creating a virtualized floppy disk controller

Floppy disk controllers are required for a number of older operating systems, especially for installing drivers. Presently, physical floppy disk devices cannot be accessed from virtualized guests. However, creating and accessing floppy disk images from virtualized floppy drives should work. This section covers creating a virtualized floppy device.

An image file of a floppy disk is required. Create floppy disk image files with the dd command. Replace /dev/fd0 with the name of a floppy device and name the disk appropriately.

# dd if=/dev/fd0 of=~/legacydrivers.img

This example uses a guest created with virt-manager running a fully virtualized Fedora installation with an image located in /var/lib/libvirt/images/Fedora.img.

Create the XML configuration file for your guest image using the virsh command on a running guest.
```
# virsh dumpxml Fedora > Fedora.xml
```
This saves the configuration settings as an XML file which can be edited to customize the operations and devices used by the guest. For more information on using the virsh XML configuration files, refer to Chapter 33, Creating custom libvirt scripts.

Create a floppy disk image for the guest.

# dd if=/dev/zero of=/var/lib/libvirt/images/Fedora-floppy.img bs=512 count=2880

Add the content below, changing where appropriate, to your guest's configuration XML file. This example is an emulated floppy device using a file-based image.
```
<disk type='file' device='floppy'>
        <source file='/var/lib/libvirt/images/Fedora-floppy.img'/>
        <target dev='fda'/>
</disk>
```
Force the guest to stop. To shut down the guest gracefully, use the virsh shutdown command instead.
```
# virsh destroy Fedora
```
Restart the guest using the XML configuration file.
```
# virsh create Fedora.xml
```

The floppy device is now available in the guest and stored as an image file on the host.