IBM Support

i Partition Hosting a Virtual SCSI i5/OS Client Partition

Technote (troubleshooting)


When using the IBM i operating system for V6R1 on POWER6-based systems, it is now possible for an i partition to be installed and operated without physical I/O adapters assigned to the partition. Disk units, optical devices, and Ethernet support can be provided using virtual I/O adapters. i partitions can operate as the virtual I/O server or the virtual I/O client.

Resolving the problem

When using the IBM i operating system for V6R1 on POWER6-based systems, it is now possible for an IBM i partition to be installed and operated without physical I/O adapters assigned to the partition. Disk units, optical devices, and Ethernet support can be provided using virtual I/O adapters. A partition using virtual adapters can be referred to as an i Client Partition or i hosted partition.

The hosting operating system can be VIOS or an i partition. It can provide virtual disk units, virtual optical drives, and virtual Ethernet adapters to the i Client Partition. The HMC is used to configure a virtual SCSI server adapter in the hosting partition and a virtual SCSI client adapter in the client partition. (Each adapter is mapped to one client adapter in a one-to-one relationship). The virtual SCSI server adapter and virtual SCSI client adapter become the SCSI transport or connection between the hosting partition and the client partition. Each server/client adapter pair can support up to 16 virtual disk units and up to 16 virtual optical devices.
At Release 710 Tech Refresh 8 and up, IBM i Virtualization has increased the number of virtual disks per VSCSI adapter from 16 to 32 on an IBM i client partition.

Once the virtual SCSI server adapter is configured, a container on the host operating system is configured to contain any virtual disk units or virtual optical drives that will be made available to the client partition. In the i operating system, this container is called a network server description (NWSD).

The HMC or IVM may be used to configure Ethernet adapters. This can be a logical host Ethernet adapter (LHEA) or virtual Ethernet. In the case of virtual Ethernet adapters, a hosting partition requires additional configuration to map between the public network the hosting partition is connected to and the private virtual LAN the client partition is connected to.

**NOTE** When upgrading, saving the IFS and/or NWSSTG, it is best practice to have the NWSD's on the host partition to be varied off.

For 4096 disk sector support at 7.2 with D/TD840 or D/T6B4E-050 drives, Please see for minimum firmware levels and PTFs.

Concurrent removal of external and virtual storage devices whether configured or non-configured is NOT supported by IBM i.

The support statement isn't limited to virtual (attached) disk. Removing external storage LUNs from an active partition is NOT supported on IBM i, regardless of whether they are attached natively or via a virtual adapter. Virtual SCSI disks are also considered "external" storage by the client even when the backing hardware on the server partition are internal storage.

As for removing the volume group, it doesn't matter how they are connected (vSCSI, NPIV, or Natively), the volumes should always be removed from the configuration first, then the partition shut down, then the volume group can be destroyed/removed.

The partition should be shutdown prior to removing or unassigning and virtual disk units or LUNs.


Documentation for configuring an i partition hosted by another i partition can be found in the Logical Partitioning Guide at the following Web site:

See the section entitled To create an IBM i logical partition that uses IBM i virtual I/O resources using the HMC.


Requirements include:

o POWER6 Servers with Brand of "I" (models 9406) or "S" (synergy). POWER6 servers with Brand of "P" are not supported. All POWER7 Servers.
o Server firmware: EM320_040_031 or later
o HMC: Version 7.3.2 Service Pack 0 or later
o i Client: V6R1M0
o i Host: V6R1M0
Common Problems

Errors varying on the network server description ( NWSD)

Message CPDC300 RC2, CPFA0A9, CPD8FFF X'00000063' :
The error occurs attempting to vary on the NWSD. Apply PTF SI30443 or supersede to the hosting LPAR (the one with the NWSD).

Message CPDB1AD rc 0009:
Problem: Power controlling set to YES in NWSD, partition profile set to control power.
Resolution: Choose one or the other as the power control. Consider changing the NWSD to PWRCTL *NO until it is configured.

Message CPDB1AD rc 0002:
Problem: SCSI client any, but no LPAR specified in NWSD.
Resolution: Instead of partition of any, consider configuring the server and client SCSI adapters to specify the server/client LPAR and adapter.

Altering the Network Storage size:
It is not supported to increase or decrease an existing network storage size. Creating additional storage space is recommended to increase the size of disk space on the partition. There are no ALERT messages generated when changing this and it will allow the change to complete, however, the partition will fail to boot.

The reason this change is allowed is because there is no way to determine the operating system within the storage space
and this option is acceptable for Linux and Window operating systems.

You may reference Informational APAR II14509.

Note: If an existing network storage space is altered, a scratch reload of the partition will be required

Installation errors

B2xx8141 on D-mode IPL to virtual optical:
This error indicates that the image is corrupt or not the I_Base LIC DVD. Work with Image Catalog Entries. Verify the LIC CD shows mounted (mount, if necessary). Use Option 12=Work with volume on the I_Base CD image, Option 5=Display. Scroll down to the MEDIA FORMAT. To IPL, it should be *ISO9660 or *UDF. Option 11=Work with object links should show a file RS610_x (where x is the resave level). If more than one image catalog is mounted or other physical optical devices are active, exclude them by adding the devices to the restricted device resources list in the network server description (NWSD).

Cross reference information
Segment Product Component Platform Version Edition
Operating System IBM i 6.1
Operating System IBM i 7.1

Historical Number


Document information

More support for: IBM i

Software version: 6.1, 6.1.0, 6.1.1, 7.1, 7.1.0

Operating system(s): IBM i

Reference #: N1013856

Modified date: 04 March 2013

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