In-Place upgrade , good or bad ?

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Is really In-place upgrade (RHEL 6 to RHEL 7) good option for SAP Hana hosts RHEL 6 servers ? Since, RHEL 6 support coming to end in near future, what is world wide industries strategy for RHEL 6 ?

Responses

Hi Sudharsan,

There is no "world wide industries strategy" - everything depends on the individual and specific needs. But one thing's for sure :
Replacing RHEL 6 with RHEL 7 brings along a lot of advantages - not to speak of the many improvements and enhancements. :)

Regards,
Christian

Yes Christian is right, depends on individual organization requirements & standards. In place-upgrade from RHEL6 to 7 is supported, please refer this article for detailed approach https://access.redhat.com/solutions/637583

Also, look at the customers' comment at the end. This has to be carefully drafted, you would need to take care of backups, roll back procedures if fails etc., You may also look at the "Package Groups" which are supported for upgrade. So, you may have to trim down your system to the basic one and try upgrade. All the best!

Hi Sudharsan,

In addition to Sadashiva's useful hints - if even possible perform a fresh RHEL 7 installation ... this is what I recommend at least. :)

Regards,
Christian

I'd personally never do an in-place upgrade (i.e. major release such as from 6.x to 7.current) unless it's on a server I don't care about and can reload on a whim. I have found/seen the instructions on it, one victim followed the directions I discovered from Red Hat and they regretted it later, we had advised against it.

That being said, if you wish to endure contact support and dealing with unexpected consequences, have that time built in the time necessary to suffer a potential outage. Just be ready. Perhaps P-to-V a system if possible to take it's place if things go south.

I am working on an in-place upgrade from RHEL6 to RHEL7. I'm doing it on a completely disposable clone of a VM. I'm taking snapshots at steps where I think I've made some progress. So far, I have to completely agree with R. Hinton and Christian Labisch. in-place upgrade is a bad idea.

Hi Sudharsan,

Others already gave you very fair and honest advice.

If you can avoid it, it is better to do clean RHEL 7 installations. However, sometimes that is not practicable or even possible.

Red Hat itself has an official statement on support upgrades between major versions of Red Hat Enterprise Linux:

https://access.redhat.com/solutions/21964

Basically, here is Red Hat's summary:

Red Hat currently supports only upgrades from Red Hat Enterprise Linux 6 to Red Hat Enterprise Linux 7 for specific/targeted use cases only. 

Regards,

Dusan Baljevic (amateur radio VK2COT)

I also think an in place upgrade from RHEL6 to RHEL7 is best avoided, and not only because it is usually better to start clean. The big change in my view between RHEL6 to RHEL7 is the move from separate directories such as /bin and /usr/bin to a single /usr/bin directory with /bin becoming a symbolic link to /usr/bin and similarly for /lib, /lib64 and /sbin, which means if the upgrade fails half way through there is a lot to tidy up, probably using a rescue image as the result may not boot, as I found out some time ago when the corresponding Fedora update failed on one of my installs. The RHEL6 to RHEL7 update also introduces systemd which might also causes problems with start up scripts. I suspect an in place update from RHEL7 to RHEL8 won't be as bad, though a clean install will still be the preferred option.