I am moving a small business website to a new host without changing the domain. Will this affect their ranking in Google? Is there any particular way I should change the DNS to make sure that its ranking on Google is not disturbed?
I usually don't see any ranking changes when changing host. I had once the situation where rankings were lower for about a month but then came back to normal. There could have been other reasons for this though.
There are two situations I can think of where rankings could be affected:
- moving strongly interlinked websites to a single host
- moving to a low performance host
Bonus: moving to a host away from the country of your target user group
As long as your website doesn't go down in the process of moving it and you keep the same domain everything should be fine. If your website goes down for a long period of time then you might get indexed by the Googlebot and you might have to wait 4 to 6 weeks to get where you were but this very unlikely. I have changed hosts before several times and I have never encounter this problem though.
Also you can read this.