upgrade ubuntu 14 to 16....better and save

Hi I know there is a document about upgrading from 14 to 16


PROBLEM: last time I fail to upgrade, end up I restore the image and cause a lot other side issues...SSH screw up....firewall screw up

QUESTION: to reduce the risk fail upgrading, what is the best strategy to do? I don't mind open a new identical Linode for duplicate but how about virtulamin? upgrading a live sever is a "real hazzle".....



Howdy -- yeah some people like to do live upgrades, others prefer to migrate their domains to a new server.

Which you do comes down to personal preference.

If you decide you'd prefer to migrate your domains to a new server, there's instructions on how to do that here:


I roughly go through the document, one concner

1) "same license on both servers during your migration." s so I can input same licence key on new server and that won't kill the old one?

2) new server has new ip, any concern it will affect other software?

Yup, that's correct, you can use the same license on both servers during your migration. It won't do anything bad to the other server.

Regarding the IP, this is a common method to migrate, and it's normal to have a new IP when you're migrating to a new server... is there a specific software concern you have? Is there a particular piece of software you're concerned about?

I think most concern the is DNS pointing to new IP, how to I know it is point to new ip or old ip? because DNS is alwasy something takes time pointing to another server...make sense?

It can take a little time for DNS to update when switching from one server to another.

If you're using your Virtualmin server as a DNS server, the instructions above offer steps that temporarily reduce the DNS cache time during the transition. That's done in the section "DNS TTL".

However, we also recommend making changes such as migrations late at night, perhaps on a Friday, so it's outside of business hours.

I have stupid question...sorry I'm not a very very tech guy

without DNS pointing to new server, can I check all website on new sever "locally" to see before playing around with DNS TTL?