9.5. Managing Storage Controllers in a Guest Virtual Machine

Procedure 9.10. Creating a virtual SCSI controller

1. Display the configuration of the guest virtual machine (Guest1) and look for a pre-existing SCSI controller:

   # virsh dumpxml Guest1 | grep controller.*scsi
   

   Copy to Clipboard Toggle word wrap
   If a device controller is present, the command will output one or more lines similar to the following:

   <controller type='scsi' model='virtio-scsi' index='0'/>
   

   Copy to Clipboard Toggle word wrap
2. If the previous step did not show a device controller, create the description for one in a new file and add it to the virtual machine, using the following steps:
   1. Create the device controller by writing a <controller> element in a new file and save this file with an XML extension. virtio-scsi-controller.xml, for example.

      <controller type='scsi' model='virtio-scsi'/>
      

      Copy to Clipboard Toggle word wrap
   2. Associate the device controller you just created in virtio-scsi-controller.xml with your guest virtual machine (Guest1, for example):

      # virsh attach-device --config Guest1 ~/virtio-scsi-controller.xml
      

      Copy to Clipboard Toggle word wrap
      In this example the --config option behaves the same as it does for disks. Refer to Procedure 13.2, “Adding physical block devices to guests” for more information.
3. Add a new SCSI disk or CD-ROM. The new disk can be added using the methods in sections Section 13.3.1, “Adding File-based Storage to a Guest” and Section 13.3.2, “Adding Hard Drives and Other Block Devices to a Guest”. In order to create a SCSI disk, specify a target device name that starts with sd.

   # virsh attach-disk Guest1 /var/lib/libvirt/images/FileName.img sdb --cache none
   

   Copy to Clipboard Toggle word wrap
   Depending on the version of the driver in the guest virtual machine, the new disk may not be detected immediately by a running guest virtual machine. Follow the steps in the Red Hat Enterprise Linux Storage Administration Guide.