(or not using) NIM
NIM - the AIX Network Installation Manager - allows you to install and maintain multiple hosts from the one master. Among people newer to AIX, NIM is often left on the backburner. With the VIO Virtual Media Library, a good deal of the NIM master's functionality has alternatives, at least if you're building LPARs which are VIO clients on the same system as the VIO server itself.
NIM still has its uses - especially for providing a source for building across to a different server or a different site. Some AIXers wouldn't be without NIM. Others tend either to live without NIM entirely or build an initial NIM server and never touch it again.
Part of the hesitation about NIM is confusion about some of its components, so it may be worth knowing of some helpful sources for information about NIM.
If you're a little NIM numb and in need of being unconfused, an excellent start is the AIX Virtual User Group Webinars. There you can download a 90 minute session on NIM basics and another one on more advanced topics.
What's the SPOT?
In those presentations, Steve Knudson explains what on earth is meant by SPOT and lpp_source. Here's my transcription along with my comments:
The lpp_source is a directory to hold installp images from the AIX media.
The spot - shared product object tree - is a /usr file system that we create from the lpp_source. Clients use commands from the spot during the install process. When the network image first comes down and the client first begins to install, he [you've got to admire someone who calls LPARs "he"] has to run commands, and the commands aren't all included in the boot image. He's got to run mkvg to create a root volume group. He has to run mklv to create logical volumes, mkfs to create file systems. He finds those commands in an NFS-mounted SPOT. That's why we have a /usr NFS-mounted file system as well as an lpp_source.
The Webinars cover lots of other
explanations and provide some very helpful presentation materials.
If you're after a little more info on NIM, you could have a look at this article by Jaqui Lynch from the IBM Systems Magazine called Simplifying with NIM. Jaqui points out that
"NIM basically provides a central point of management for installing and maintaining AIX images for both LPARs and individual servers."
She also shows how NIM can take
care of mksysb images for multiple LPARs and servers over several
different sites. Have a look at her more recent article on the same
AIX LPAR and Server Management with NIM.
The IBM Redbook NIM from A to Z in AIX 5L is still valuable, even though it was written for AIX 5.3 and we're now testing the AIX 7 Open Beta.
(Incidentally, since NIM must be at the latest level, you can't install the AIX 7 Open Beta mksysb from a lower level NIM server. You can follow this issue on the AIX 7 Open Beta user forum).
Update from AIX 7 Open Beta forum: