Migration from CentOS 6 to Ubuntu 20

Hello,
I’m definitely ready to migrate my old CentOS 6 server to a brand new Ubuntu 20.04.
I have followed the instructions from the migration page of Virtualmin and made a backup of everything then i have sent the files to the new server and started to restore all domains.

The restoration stopped because of an error about the creation of an account on mysql. It was a mess and I have decided to migrate all domains one by one.

My issues and questions :
I had php 5 and mysql 5 on the old server.
The defaults on the new one are php 7 and mysql 8. I have installed php 5 but it doesn’t seem to like mysql 8 for wordpress installation. I think I need to upgrade everything on the old server before the migration.

Question about DNS : when I migrate the dns records, the A records change to the new ip but the SOA and NS will remain on the old hostname. Should I change them manually ?

It seems there are some problems when testing sites. Sometimes when I test a site on the new server (before switching DNS) I see another virtual server but not the one I wanted to test. Somebody is aware of this issue ?

The Postfix is not running on the new server, can it be because of the restoration process of Virtualmin ? I don’t think so but I feel it is strange

Thanks for your help

Hello i read some of your threads.

I can’t help you but:
My advice is to ask / hire one for support, if license Virtualmin then you can ask VM support, they don’t normally themself do stuf on boxes of clients. ( sometimes… yup)

This while you have to long now problems migrating things.

And some parts in your topics missing as real all versions used of the software meaning for example php 5 is not the same as php 5.6x :wink:

You habe to make also a complete list they need was you did use on old box on versions and configs, and also if you need those versions on new box, while better to upgrade such things if possible!

Sorry i am so harsh… is only my advice / opinion. :wink:
I do wish you succes with it ofcourse

Oyea old stuff always have also old bugs in it yes or no completly solved that is taken care for.

YOUR APPS software used for and by users versions and plugins addons need almost sure updating to newer.

If the LE cert is not so important but custommers /you want to stay with those very old EOL versions hmmm that is for example if using php 5.x only for a i guess now “short” … period of time with php 5.6.x and some backported security sofar i know if using older versions then the php5.6 and needed do some websearch about those and their support. (yes you can go on with to old EOL versions but then again you have to expect troublesome times when they die…)

It shouldn’t be that bad if you kept it updated. OS 6 only reached end of life a year ago.

Not a bad idea. Longer, but at least you can fix each issue as it comes.

Good idea if you can do that, but be careful. Make sure you have complete backups of each domain.

Is it checked in the boot up sequence?

Go to the Webmin panel / System / Boot up and Shutdown tab and find postfix in the list to see if it’s checked to start on bootup.

With regard to Wordpress, I don’t know how many Wordpress installations you have, but the absolutely best, most flawless way to move them is with the All-in-one Migration tool plugin for Wordpress.

I’ve used it around 30 times so far and never had a single failure.

Hello,
thanks for your answer
I understand I have waited too long before migrating things. I was still relying on Php 5.3 and not even 5.6 and some of my sites are still very old Wordpress versions. That is the reason of difficult migration. Maybe the Let’s Encrypt issue was a good way to force me leaving CentOS 6 and old versions of php and MySQL

After some days of issues, I have finally found a way to migrate the most recent sites which were already in php 7.4 and it works quite fine. Let’s Encrypt is ok for all these sites and I’m learning new tips about web hosting every day :slight_smile:

I made a mistake by putting several questions in the same topic : I’ll make several topics for remaining questions but the most difficult part of the migration is about wordpress and php version so I should manage to correct everything myself.

Thanks again for helping me and answering my question because it helps to know that people care :slight_smile:

Thanks for your tips.
About postfix, yes it is enabled at boot but there is an error. I’ll make a separate topic if I don’t find how to fix it myself.

The migration of the sites one by one is quite ok. I have 20 sites and half are really transfered. All full backups are done and it’s quite easy to move them if the php version is ok :slight_smile:

About all in one migration for Wordpress I’ll check it out. But my issue is the fact that some wordpress are very old and don’t work with php 7.4. I don’t know how the plugin can handle that : i would need to export on the old server and import in the new one with the plugin ?

thanks for your support

What exact error message was it?

I’m sorry I had not kept the error and tried to migrate sites one by one.
I’ll make a different post if I get this error again
thanks