Dear Gudelli
I see no need for "multiple paths" in both release upgrade and server HW. For the latter, just find a server with sufficient basic resources with special attention to matching IO (LAN, WAN, tape controller, etc.) Pay attention if the old server uses any special HW such as Fax Card, or optical library, etc. If none, your are in luck for this part.
Some documents about this can be lost in time as things move fast in technology world. Basically, the high level view is that you need first to do save entire system (and make sure to take time to carefully review the job log after it finishes to ensure no serious components are not saved for whatever reason and address any issue that is significant). Then you need to do a "scratch" install the new IBM i release in a new machine together with all IBM i licensed programs needed. Then finish with applying the latest level of all PTFs. Then, in the new machine, manually restore each step as described in RESTORE part of the PDF file I attach below. (Do NOT use GO RESTORE --> an option for restore entire user data menu for this.) In each restore step, you need to remember to use OPTION(*NEW) to prevent old version of system objects from tape overwriting over the new ones on disk and causing havoc. Then review the detailed job log for any issues in each step of RSTxxxx command and address the siginificant issue found. Please take note that there is no in-place OS upgrade here as it is only for N+2 release upgrade which is not your case here. Therefore no need for multiple paths.
One possible issue I foresee when moving to a very old AS/400 machine to a more recent Power System one is whether the tape media you save the data from the old machine is still supported on the new machine or not. This can be a show stopper. So, you had better check about this first. Otherwise it can waste your time trying to plan any thing else.
Next possible show-stopper obstacle is that at IBM i 6.1, there was a major change in security-related aspect that needs all program objects to be RETRANSLATED and THIS REQUIRES THAT ALL PROGRAM OBJECTS HAVE what is called OBSERVABILITY in them. Any program objects without observability have no hope of getting translated and will not run in IBM i 6.1 and later releases. You must compile these problematic program objects from their source codes instead. More information on this from this IBM redpaper IBM i Program Conversion: Getting Ready for 6.1 and Beyond at https://redbooks.ibm.com/abstracts/redp4293.html. For V5R4, there is a tool (delivered as PTFs) you can run to scan for program objects with no observability. For V4R3, you are on your own manual effort for such identification.
Next possible obstacle may lie in the application environment itself. You need to supply some information about this for me to see. Is it an application from a well-known ISV ? What language is it developed in? Do you still have complete source codes? etc.
If I were you and if all possible planning obstacles above are overcome, I would set an expectation to all involved that there needs to be a test case first in which you try the actual save and restore and then a thorough application test. Do expect to encounter more than a few issues. You should also download all Memo to Users from release 6.1 to the one you target for and study and keep them for future reference. They can help you address some issues encountered during the test. Download them from here https://www.ibm.com/docs/en/i/7.1?topic=information-memo-users Select each IBM i release from the top left corner of the web page. There is none for 6.1 from this URL. I may still have its PDF file. Let me know when you need it.
Last time I did this in 2018, I did not have much problem during the save and restore but many issues came up during the cut over (no test for this customer). But Google search helped me to find many IBM Technotes on such thing I needed as restoring AJS job entries, basic job scheduler entries, NetServer config, Directory entries, TCP host tables, RDB direcory entries, and SNADS config. These were somehow not restored during the manual restore. But in the end, things settled down to normal after a few days. It helped when the customer allowed to access their system from my home country after I went back home.
This IBM Technote can also give you some more information : IBM i Upgrade Planning at https://www.ibm.com/support/pages/upgrade-planning.
There are still many more tidbits details involved here that I have no time to mention here. It is essential to have someone who used to perform this kind of migration before. One choice you can think of is to pay for IBM Expert Lab team to come do or guide you on doing this test case.
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Education is not the learning of facts but the training of the mind to think. -- Albert Einstein.
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Satid S.
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Original Message:
Sent: Tue March 28, 2023 08:31 AM
From: Gudelli Suresh
Subject: OS upgrade from V5R4 and V4R3 to V7R4/V7R5
Hello Team,
Greetings of the day.
We have couple of AS400 lpars whose OS versions are at V5R4 and V4R3 whose supported has ended way back. As customer is unable to access and facing issue on the server we have suggested for an upgrade.
I have been involved in the upgrades from V7R2 to V7R4/V7R5 but this seems to be critical as it involved multiples paths to bring it to the latest version, also the hardware needs to be upgraded but not sure even hardware also involved multiples paths.
Can you please help me on how and what to consider for an upgrade and if you have document or wiki would be helpful.
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Gudelli Suresh
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