Example of a multipathed SCSI tape and medium changer device configuration

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Provide one virtual SCSI device for each configuration path.

About this task

This example provides a configuration for the topology as shown in SCSI tapes and medium changers as virtual SCSI devices.

Procedure

  1. Create a domain configuration-XML file with one configured virtual HBA for each host device.
    This configuration groups all virtual SCSI devices that represent the same host device in an own virtual HBA.
    <domain type="kvm">
  <name>VM1</name>
  ...
  <devices>
     ...
    <controller type="scsi" model="virtio-scsi" index="0">
       <address type="ccw" cssid="0xfe" ssid="0" devno="0x0002"/>
    </controller>
    <controller type="scsi" model="virtio-scsi" index="1">
       <address type="ccw" cssid="0xfe" ssid="0" devno="0x0004"/>
    </controller>
    ...
  </devices>
</domain>
  2. Create separate device configuration-XML files for the SCSI tape device, both connected to the virtual HBA 0.
    1. The first file configures SCSI device name 0:0:0:0, which is the path of SCSI LUN 0 via SCSI host 0.
      <hostdev mode="subsystem" type="scsi">
     <source>
        <adapter name="scsi_host0"/>
        <address bus="0" target="0" unit="0"/>
     </source>
     <address type="drive" controller="0" bus="0" target="0" unit="0"/>
</hostdev>
    2. The second file configures SCSI device name 1:0:0:0, which is the path via SCSI host 1.
      <hostdev mode="subsystem" type="scsi">
     <source>
        <adapter name="scsi_host1"/>
        <address bus="0" target="0" unit="0"/>
     </source>
     <address type="drive" controller="0" bus="0" target="0" unit="100"/>
</hostdev>
  3. Create separate device configuration-XML files for the SCSI medium changer device, both connected to the virtual HBA 1.
    1. The first file configures SCSI device name 0:0:0:1, which is the path of SCSI LUN 1 via SCSI host 0.
      <hostdev mode="subsystem" type="scsi">
     <source>
        <adapter name="scsi_host0"/>
        <address bus="0" target="0" unit="1"/>
     </source>
     <address type="drive" controller="1" bus="0" target="0" unit="1"/>
</hostdev>
    2. The second file configures SCSI device name 1:0:0:1, which is the path via SCSI host 1.
      <hostdev mode="subsystem" type="scsi">
     <source>
        <adapter name="scsi_host1"/>
        <address bus="0" target="0" unit="1"/>
     </source>
     <address type="drive" controller="1" bus="0" target="0" unit="101"/>
</hostdev>