VIOS FAQ
VIOS frequently asked questions
The Virtual I/O Server is an appliance that provides virtual storage and shared Ethernet adapter capability to client logical partitions on POWER5 systems. It allows a physical adapter with attached disks on the Virtual I/O Server partition to be shared by one or more partitions, enabling clients to consolidate and potentially minimize the number of physical adapters required.
Yes. The below VIOs website contains links to documentation, hints and tips, VIOS updates and fixes.
The VIOS documentation can be found online in the below link.
N_Port ID Virtualization(NPIV) is a standardized method for virtualizing a physical fibre channel port. An NPIV-capable fibre channel HBA can have multiple N_Ports, each with a unique identity. NPIV coupled with the Virtual I/O Server (VIOS) adapter sharing capabilities allow a physical fibre channel HBA to be shared across multiple guest operating systems. The PowerVM implementation of NPIV enables POWER logical partitions (LPARs) to have virtual fibre channel HBAs, each with a dedicated world wide port name. Each virtual fibre channel HBA has a unique SAN identity similar to that of a dedicated physical HBA.
The minimum requirement for the 8 Gigabit Dual Port Fibre Channel adapter, feature code 5735, to support NPIV is 110304. You can obtain this image from the http://www-933.ibm.com/support/fixcentral/
Virtual SCSI is based on a client and server relationship. The Virtual I/O Server owns the physical resources and acts as server, or target, device. Physical adapters with attached disks on the Virtual I/O Server partition may be shared by one or more partitions. These partitions contain a virtual SCSI client adapter that sees these virtual devices as standard SCSI compliant devices and LUNs.
A shared Ethernet adapter is a bridge between a physical Ethernet adapter or link aggregation and one or more virtual Ethernet adapters on the Virtual I/O Server. A shared Ethernet adapter enables logical partitions on the virtual Ethernet to share access to the physical Ethernet and communicate with stand-alone servers and logical partitions on other systems. The shared Ethernet adapter provides this access by connecting the internal VLANs with the VLANs on the external switches.
See the http://www14.software.ibm.com/webapp/set2/sas/f/vios/documentation/datasheet.html for supported storage and configurations.
1. AIX 5.3 and AIX 6.1 TL 2
2. SUSE LINUX Enterprise Server 9 for POWER
3. Red Hat Enterprise Linux AS for POWER Version 3(update 2 or newer)
4. Red Hat Enterprise Linux AS for POWER Version 4
5. IBM i
Virtual SCSI disk devices are standard SCSI compliant devices that support all mandatory SCSI commands. Solutions that have special requirements at the device level should consult the IBM Solutions team to determine if the device meets your requirements.
The VIOS datasheet includes some information on VSCSI solutions.
That is, given a physical SCSI device(ie LUN), with user data on it, that resides in a SAN environment; can this device be allocated to a VIOS and then provisioned to a client partition and used by the client as is?
No, this is not supported at this time. The device cannot be used as is, virtual SCSI devices are new devices when created, and the data must be put onto them after creation. This typically would require some type of backup of the data in the physical SAN environment with a restoration of the data onto the virtual disk.
Server and hosting partition is synonymous, as is client and hosted. The server/hosting partition(s) own physical resources and facilitates the sharing of the physical resource amongst the client/hosted partition(s).
The Linux and IBM i operating systems do provide various virtual I/O server/hosting features(virtual SCSI, ethernet bridging, etc). AIX does not provide virtual I/O server/hosting capabilities. There is only one product named the Virtual I/O Server. It is a single function appliance that provides I/O resource to client partitions, and does not support general purpose applications.
The VIOS is not AIX. The VIOS is a critical resource and as such, the product was originally based on a version of the AIX operating system to create a foundation based on a very mature and robust operating system. The VIOS provides a generic command line interface for management. Some of the commands in the VIOS CLI may have common names with AIX and Linux commands. These command names were chosen only because they were generic, the flags and parameters will differ. While some of the VIOS commands may drop the user into an AIX-like environment, this environment is only supported for the installing and setup of certain software packages(typically software for managing storage devices, see the VIOS's Terms and Conditions). Any other tasks performed in this environment are not supported. While the VIOS will continue to support it's current user interfaces going foward, the underlying operating system may change at any time.
The sole purpose of the oem_setup_env VIOS CLI command is for ease in installing and setting up certain software packages for the VIOS. See the VIOS datasheet for a list of supported VIOS software solutions.
Please see the section titled "Planning for Virtual SCSI Sizing Considerations" in the VIOS online pubs in InfoCenter.
The VIOS online pubs in InfoCenter include sections on sizing for both Virtual SCSI and SEA. For Virtual SCSI, please see the section titled "Planning for shared Ethernet adapters".
In addition, the WorkLoad Estimator Tool is being upgraded to accommodate virtual I/O and the VIOS.
Typical multipathing solutions provide two key functions: failover and load balancing. MPIO for VSCSI devices does provide failover protection. The benefit of load balancing is less obvious in this environment. Typically, load balancing allows the even distribution of I/O requests across multiple HBA's of finite resource. Load balancing for VSCSI devices would mean distributing the I/O workload between multiple VIOS's. Since the resources allocated to a given VIOS can be increased to handle larger workloads, load balancing seems to have limited benefit.
The Advanced POWER Virtualization feature is a package that enables and manages the virtual I/O environment on POWER5 systems. The main technologies include:
- Virtual I/O Server
- Virtual SCSI Server
- Shared Ethernet Adapter
19) What are some of the restrictions and limitations in the VIOS environment?
- Logical volumes used as virtual disks must be less than 1 TB in size.
- Unique device identifier(UDID)
MPIO uses the UDID method.
Most non-MPIO disk storage multi-pathing software products use the PVID method instead of the UDID method. Because of the different data format associated with the PVID method, customers with non-MPIO environments should be aware that certain future actions performed in the VIOS LPAR may require data migration, that is, some type of backup and restore of the attached disks. These actions may include, but are not limited to the following:
- Conversion from a Non-MPIO environment to MPIO
- Only Ethernet adapters can be shared. Other types of network adapters cannot be shared.
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