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Showing posts with label vio. Show all posts
Showing posts with label vio. Show all posts

The basics of VIO


VIO technologies consist of servers, software, and various commands.

VIO servers

VIO technology is based on the idea of having special LPARs that manage the disk and network resources that other LPARs use on the same pSeries or IBM System p servers. Instead of the individual network and disk resources being carved out on an LPAR-by-LPAR basis (especially in cases where there wouldn't be sufficient resources for all the LPARs to possess what they require to function), one or two VIO servers are given control of these resources and share them out to the other LPARs (VIO client LPARs).

VIO software

This VIO server runs a special version of the AIX operating system, with an additional software package called IOS. This software comes bundled and is managed independent of the usual operating system commands (for example, installp) and versioning structure (technology levels). It is similar to how HMCs have specialized software loaded onto a Linux kernel for a specific purpose.

Note: Installing third-party software or altering the operating system through any means outside of the IOS typically invalidates support from IBM, so it's best to avoid modifying the server in any nonstandard, non-VIO way.

The VIO user ID and commands

Instead of using the root user ID to issue commands, an administrative user ID—padmin—is used for all of the VIO controls. This user ID has a shell called the IOS command-line interface (ioscli) that runs a unique set of commands for managing devices assigned to the VIO servers. Many of these commands are similar to regular AIX commands (for example, lsdev) but use different flags and command structures (for example, lsdev –dev). But, most of the superuser level commands are new and perform many different operations at once. In fact, when administered properly, systems administrators will rarely have to become root. Helpful padmin commands include:

  • help: This command lists all of the commands available in the ioscli. If you pass a specific command into it, such as help updateios, you can see the specific flags and syntax for that command.
  • cfgdev: This command is the equivalent of the cfgmgr command and detects new physical and logical devices added to the VIO server.
  • oem_setup_env: This command is the equivalent of running su – root but without the need to enter a password. Again, you will rarely have to become root on a VIO server.

  • mkvdev: This command manages the virtual devices that you create and serve up to the VIO client LPARs.
  • mktcpip, lstcpip, and rmtcpip: These commands manage your networking from the command line and circumvent the need for utilities such as smitty tcpip.
  • lsmap: This command shows the relationships between disk resources and VIO client LPARs.