I have compiled a brief list of "gotchas" from various sources from IBM for when you decide to upgrade to AIX 5L. It is not by any means a complete list, but it does touch on some of the idiosyncrasies of 5L and things to watch out for. Step one- Check Current System for Corruption: Make sure you have a stable system BEFORE you do the migration. You need to make sure that your current level of AIX is stable, with no ODM corruption or fileset problems, before attempting. PRE Migration Checks Make sure the installed Licensed Program Products are consistent: #lppchk -v #lppchk -c #lsvg rootvg You should get no output from the preceding command. Any output is error output and should be corrected. Make sure none of you filesets have been broken: #lslpp -l|grep BROKEN Broken base filesets are corrected by forcing the install of the base fileset. Broken PTFs are corrected by reinstalling the PTF in the committed state. Make sure all of the user definitions are correct in the user database: #usrck -n ALL Do the same for the groups: #grpck -n ALL If you find errors, you can correct them by replacing the -n flag with the -t flag. Step two - Check CD-ROM and Other firmware! Make sure you check the CD- ROM drive BEFORE you start, or the system may not boot......... # lscfg -vl cd* If Part number is 04N2964 and ROS level or ID is less than 1_04 you NEED to have the firmware upgraded FIRST (Retain Tip H1332) If the part number is not 04N2964 you should be fine. Make sure your firmware on your disks, and machine and devices is up to date...You will get an unrecognized client program format error if you do not have up to date firmware and result in a failure to boot from hard disk. CHECK your adapters....Not all adapters are supported with 5L or in 64 bit mode..... http://www-1.ibm.com/servers/aix/os/adapters/51.html Step three - Check system space: You must have 64 megabytes of physical memory. Paging space for initial is 64 megabytes. You must have space for 5L. It is a much bigger kernel / root 8 MGS (double of 4.3) /usr 385 MGS /var 4 MGS /tmp 32 MGS /opt 4 MGS (will be created if it doesn't exist.) Dumpspace required based on memory: < 12 GB 1GB 12 <24 2GB 24 < 48 3GB >=48 4GB Step Four : Remove Software Packages Remove any AIX Toolbox for Linux applications if you installed them, before doing migration. If you install bos.terminfo or other bos.terminfo.svprint.data...DO NOT attempt to remove or deinstall once installed. This could cause errors and missing functions. You will get syschk Warning errors on installation... Step Five: Type of Kernel The 32 bit kernel continues to be supported on 5L 64 bit Kernel support is available for the following POWER based systems: 7013 Model S70, S7A 7015 Model S70, S7A 7017 Model S70, S7A, S80 7025 Model H80, F80 7026 Model H70,H80,M80 7043 Model 260, 270 7044 Model 170,270 680 Model S85 640 Model B80 660 Model 6H1 620 Model 6F1 ALL MCA adapters are only supported on 32 bit kernel Power Management is only provided under 32 bit kernel 64-bit kernel limits support to 64 bit POWER based systems, while the 32 bit kernel supports both 32 and 64 bit kernel systems. All MCA machines will notbe supported at AIX 5.2 or higher. Application Support TEST TEST TEST - make sure that your application will work with AIX 5L....It is advised that you try your applications on a demo machine, or demo node BEFORE installing on a production machine. You can do what you want, but if there is some library or some application that does not work, you are on your own......Here is some general information on compatibility: The 64 bit kernel supports both 32-bit and 64 bit applications. Application source and binaries are portable between 5L 64 and 32 bit kernel systems. Binary compatibility is provided for 32 bit applications running on earlier versions of AIX on POWER based systems, except for applications linked statically or applications dependent on undocumented or unsupported interfaces. Some system file formats have changed, and 32 bit applications processing these files MAY HAVE TO BE RECOMPILED. To take advantage of scalability improvements to 64 bit programs, all applications and libraries must be recompiled on AIX 5l. In addition existing 32 bit kernel extension and device drivers used by 64 bit applications may have to be modified in order to support the new 64 bit ABI. Kernel extensions for the 64 bit kernels run in 64 bit mode and have the scalability of larger kernel address space. Some kernel services available in 32 bit kernel are no longer provided by the 64 bit kernel, so existing 32 bit kernel extensions may have to be ported in order to be used with the 64 bit kernel. Existing 32 bit kernel extensions continue to be supported by the 32 bit kernel, but these kernel extensions are not usable by the 64 bit kernel. Not all of the kernel extensions supported for the 32 bit kernels are supported for the 64 bit kernel, particularly device drivers for i/o. A Word on MIGRATION Migration is the default installation method for 32 or any versions of Aix Version 4 of the operating system to 5L. BE sure to do a mksysb and that it completed successfully before starting. I really recommend doing on a test machine, before doing the actual production migration........or even doing a complete overwrite install to be sure that everything makes it ok....but again, that is your choice....and this is only my opinion. YOU MUST BE sure that you are root and system for your group.... #lsuser -a auth1 root you can change the value if need with : #chuser auth1=SYSTEM root OTHER users who have access MUST BE LOGGED off before you begin. Make sure you document all routes, IP addresses, hostnames etc, before you begin. You should probably have a hard copy of your system, with all the settings, just in case. (see save your system, from our web site) After you do a shutdown -F you must power off your machine and all devices...then turn the devices back on and make sure they are on before you proceed....The system will identify each peripheral during startup. During the migration, the installation process determines which optional software products are installed on the existing version of the operating system. Components from previous releases that have been replaced by new software in 5L are installed at the 5L level... If you were at 3.2, all files in the /usr/lib/drivers, /usr/lib/microcode, /usr/lib/methods and /dev are removed from the system. so non-device drivers must be reinstalled. All Aixwindows interface composer, remote customer services, Aix Windows Development Environment, Display PostScript, Performance Tools and Open GL and graPHIGS is removed. NOTE: You may have problems with your 32 bit applications if they had certain unsupported self-loadable kernel extensions, certain HFT interfaces, X11R3 input device interfaces, CIO LAN device driver interface, SCSI device configuration methods (IHVs), nlist subroutines, DCE threads, and applications compiled using POWER2 or POWER based compiler options, but executed on models other than POWER 2 or POWER. Existing code may need to be recompiled.... Binary Compatibility - If you do a migration install, you might notice that filesets on the system are in the OBSOLETE state. Obsolete filesets were installed by earlier versions of the operating system, but they remain on the current system because the migration only replaced some, but not all, of the files they contain. These filesets remain necessary for systems running mixed levels of the operating system... Before you reload or install other software, shutdown the machine and turn it off and then reboot.....or you will get kernel errors as in kernel is 4, software is 5.... These will help as well.... Release notes: http://publib.boulder.ibm.com/pseries/aixgen/relnotes/ext_relnotes.htm Software supported at 5: http://www-1.ibm.com/servers/aix/products/ibmsw/list/ Adapters supported at 5: http://www-1.ibm.com/servers/aix/os/adapters/51.html