Good old onmode -b will revert the primary - it will and cannot revert those secondaries!
So, when upgrading from 12 to 14, what you're really saving now, since 14.10.xC4W1, is having to re-instantiate your secondaries - you just bring them up under v14.10 and all required conversion will be taken care of across the cluster.
The reversion process, though, is a different beast and has not been implemented for secondaries (and I'm not even sure this would be possible.)
-> you'll have to re-create the secondaries from primary after primary got reverted.
Also, when reverting, try to be as precise as possible when choosing the 'to-version': run 'onmode -b' without any version specified to get a list of options, then pick the closest one older than the actual old version you're reverting to. E.g. when reverting to 12.10.FC12, run 'onmode -b 12.10.xC8'.
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Andreas Legner
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Original Message:
Sent: Mon April 12, 2021 10:47 AM
From: Paul Watson
Subject: Downgrade from IDS 14 to 12
That might have been the case, but now you have onmode –b. It should support any reversion of any direct update method
Cheers
Paul
Original Message:
Sent: 4/12/2021 10:27:00 AM
From: Eric Vercelletto
Subject: RE: Downgrade from IDS 14 to 12
The inplace downgrade scenario is not possible, because the new version will write "things" in disk structures that will work for version 14 and not for version version 12 anymore.
So upgrade is an irreversible operation.
If you want to downgrade "in place", this is not supported.
During upgrade, there is a phase when it is still possible to return to previous version, but once you decided to finalize the upgrade, you cannot revert.
Solutions are
- Never overwrite the 'old' $INFORMIXDIR directory, always create a new $INFORMIXDIR with the new version: easier to switch if necessary
- More than highly recommended: run a full backup from version 12 before upgrading and check it
- If upgrade goes badly, switch your environment to your old $INFORMIXDIR and restore your backup
- Another solution is to use Enterprise Replication between 2 servers to push the data from 'old server' to 'new server' and synchronize data both ways: this option lets you switch back to the 'old' server if anything happens But this is bit more work to do it and you need 2 servers
Sorry, I don't have much time now to develop on that but I know that our colleague will propose ideas ��
Eric Vercelletto
Data Management Architect and Owner / Begooden IT Consulting
KandooERP Founder and CTO
IBM Champion 2013,2014,2015,2016,2017,2018,2019,2020
Tel: +33(0) 298 51 3210
Mob : +33(0)626 52 50 68
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www https://kandooerp.org
Original Message:
Sent: 4/12/2021 8:27:00 AM
From: Sh To
Subject: Downgrade from IDS 14 to 12
Hello
We'd like to upgrade our servers from IDS 12 to IDS 14
3 servers in primary/HDR/RSS configuration.
To check/learn the process, I installed the same config on virtualbox (with demodb)
I upgraded from IDS 12 to 14, and all work fine.
But, I tried (on the same test machines) to downgrade from IDS 14 to 12 to see how it works.
So I shutted down the server, change the symbolic link to point to the old version and tried to oninit -v and it fails.
Two tries:
1)
Shell
Cannot bring server up from a higher version server rootdbsoninit: Fatal error in shared memory initialization
Online.log
10:33:05 Cannot bring server up from a higher version server rootdbs
10:33:05 oninit: Fatal error in shared memory initialization
10:33:05 IBM Informix Dynamic Server Stopped.
10:33:05 mt_shm_remove: WARNING: may not have removed all/correct segments
2)
Shell
Cannot bring server up from a higher version server rootdbsoninit: Fatal error in shared memory initialization
And nothing in online.log
Any idea?
Thanks
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Sh To
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#Informix