VIO server introduction.

The Virtual I/O Server is software that is located in a logical partition. 

This software facilitates the sharing of physical I/O resources between client logical partitions within the server. 

The Virtual I/O Server provides virtual SCSI target, virtual fibre channel, Shared Ethernet Adapter, and PowerVM™ Active Memory Sharing capability to client logical partitions within the system. 

As a result, client logical partitions can share SCSI devices, fibre channel adapters, Ethernet adapters, and expand the amount of memory available to logical partitions using paging space devices. 

The Virtual I/O Server software requires that the logical partition be dedicated solely for its use. 

--------------------------------------------------------------------------------------------------------------------------

 Why to use vio server



Using the Virtual I/O Server facilitates the following functions: 

•  Sharing of physical resources between logical partitions on the system

•  Creating logical partitions without requiring additional physical I/O resources

•  Creating more logical partitions than there are I/O slots or physical devices available with the ability for logical partitions to have dedicated I/O, virtual I/O, or both

•  Maximizing use of physical resources on the system

•  Helping to reduce the Storage Area Network (SAN) infrastructure

--------------------------------------------------------------------------------------------------------------------------
                               



Requirement for vio server.

 Minimum Hardware requirements to create the Virtual I/O Server partition: 

1.     POWER5 server,     :    the VIO capable machine.
2.     Hardware management console(HMC) : to create the partition and assign resources.
3.     Storage adapter:         The server partition needs at least one storage adapter. 
4.     Physical disk:             A disk large enough to make sufficient-sized logical volumes on it.
5.     Ethernet adapter:        Allows securely route network traffic from a virtual  Ethernet   to                                                 real network adapter.

       6.      Memory:                     At least 128 MB of memory.

--------------------------------------------------------------------------------------------------------------------------

 NOTE:                     The Virtual I/O Server provides the Virtual SCSI (VSCSI) Target and Shared Ethernet adapter virtual I/O function to client partitions. 
                            This is accomplished by assigning physical devices to the Virtual I/O Server partition, then configuring virtual adapters on the clients to allow communication between the client and the Virtual I/O Server. 



-----------------------------------------------------------------------------------------------------------------------



SUPPORTED OS AS VIO CLIENT

Virtual I/O server supports the following operating systems as virtual I/O client:
 •    AIX 
 •    SUSE LINUX Enterprise Server 9 for POWER 
  •   Red Hat Enterprise Linux AS for POWER Version 3 
  •   Red Hat Enterprise Linux AS for POWER Version 4 










Capabilities of the Virtual I/O Server 

•        Ethernet Adapter Sharing
•        Virtual SCSI disK
•        Interacts with AIX and Linux partitions

•                 The Virtual I/O Server provides a restricted scriptable command line user interface (CLI). All aspects of Virtual I/O server administration are accomplished through the CLI, including:-

                                 Device management (physical, virtual, LVM) 
                                 Network configuration 
                                 Software installation and update 
                                 Security 
                                 User management 
                                 Installation of OEM software 
                                 Maintenance tasks

•     The creation and deletion of the virtual client and server adapter is managed by the HMC GUI and POWER5 server firmware. The association between the client and server adapters is defined when the virtual adapters are created.

VIRTUAL SCSI

 •       Virtual SCSI is based on a client/server relationship. 
 •       The virtual I/O resources are assigned using an HMC. 
 •       Virtual SCSI enables sharing of adapters as well as disk devices. 
 •       Dynamic LPAR operations allowed. 
 •       Dynamic mapping between physical and virtual resources on the virtual I/O server. 

NOTE:        Virtual SCSI is based on a client/server relationship. The virtual I/O server owns the physical resources and acts as the server. The logical partitions access the virtual I/O resources provided by the virtual I/O server as the clients.

The virtual I/O resources are assigned using an HMC.

.Virtual SCSI enables sharing of adapters as well as disk devices.

>>>>>>>>                To make a physical or a logical volume available to a client partition, it is assigned to a virtual SCSI server adapter in the virtual I/O server partition. 
                                   The client partition accesses its assigned disks through a virtual SCSI client adapter. It sees standard SCSI devices and LUNs through this virtual adapter.

>>>>>>>                     Virtual SCSI resources can be assigned and removed dynamically. On the HMC, virtual SCSI target and server adapters can be assigned and removed from a partition using dynamic logical partitioning. 
                                      The mapping between physical and virtual resources on the virtual I/O server can also be done dynamically.

>>>>>>>                        A disk owned by the virtual I/O server can either be exported and assigned to a client partition as a whole or it can be split into several logical volumes. Each of these logical volumes can then be assigned to a different partition.




  EFFECT ON PERFORMNACE IF  USING VSCSI



 This is because there is an overhead associated with Hypervisor calls, and because of the several steps involved for the I/O requests from the initiator to target partition,

 VSCSI will use additional CPU cycles when processing I/O requests. This will not give the same performance from VSCSI devices as from dedicated devices.

 The use of Virtual SCSI will roughly double the amount of CPU time to perform I/O as compared to using directly attached storage. This CPU load is split between the Virtual I/O Server and the Virtual SCSI Client. 

Performance is expected to degrade when multiple partitions are sharing a physical disk, and actual impact on overall system performance will vary by environment. The base-case configuration is when one physical disk is dedicated to a partition.



VIRTUAL ETHERNET


 •         Enables inter-partition communication.
 •         In-memory point to point connections 
 •         Physical network adapters are not needed. 
 •         Similar to high-bandwidth Ethernet connections. 
 •         Supports multiple protocols (IPv4, IPv6, and ICMP). 
 •         No Advanced POWER Virtualization feature required. 


The Virtual Ethernet enables inter-partition communication without the need for physical network adapters in each partition.

 The Virtual Ethernet allows the administrator to define in-memory point to point connections between partitions.

 These connections exhibit similar characteristics, as high bandwidth Ethernet connections supports multiple protocols (IPv4, IPv6, and ICMP). 

Virtual Ethernet requires a POWER5 system with either AIX 5L V5.3 or the appropriate level of Linux and a Hardware Management Console (HMC) to define the Virtual Ethernet devices.

Virtual Ethernet does not require the purchase of any additional features or software, such as the Advanced Virtualization Feature.

Virtual Ethernet is also called "Virtual LAN or even VLAN", which can be confusing, because these terms are also used in network topology topics. But the Virtual Ethernet, which uses virtual devices, has nothing to do with the VLAN known from Network-Topology, which divides a LAN in further Sub-LANs.




 Viosbr Command


The viosbr command  is used  to back up all the relevant data to recover a VIOS after an installation.  


 The viosbr command backs up following mentioned details :-


2.      Logical devices,  such as storage pools,  clusters (VIOS Version 2.2.0.11, Fix Pack 24, Service Pack 1, or later),  file-backed storage pools,  the virtual media repository, and paging space devices.


3.     Virtual devices, such as Etherchannel, shared Ethernet adapter, virtual server adapters, and virtual-server fiber channel adapters.


4.     Device attributes for devices like disks, optical devices, tape devices, fscsi controllers, Ethernet adapters, Ethernet interfaces, and logical Host Ethernet Adapters.


   While viosbr allows you to restore mappings





Backupios  command 


 backupios is used to restore the whole VIOS operating system. 


"The backupios command creates a backup of the Virtual I/O server and places it onto a file system, bootable tape or DVD. You can use this backup to reinstall a system to its original state     after it     has been corrupted

Again, be sure to backup your VIOS environment with both viobr and backupios. Together, they give you the tools you need should something go wrong.


Updateios  command

The updateios command is used to install fixes, or to update the Virtual I/O Server to the latest maintenance level. 

to commit the installed updates, type the following command: 


# updateios -commit


To update the Virtual I/O Server to the latest level, where the updates are located on the mounted file system /home/padmin/update, type the following command: 


# updateios -dev /home/padmin/update