Migrating a website from one hosting provider to another should, if done correctly, have no impact on organic rankings; factors such as server IP address are not used as a ranking factor. Site speed, however, is a major ranking factor and since many website migrations to new or upgraded servers are done in order to increase the speed and performance of the website, ranking improvements can be seen as a result of this. The largest improvements in speed will come from migrating a website to a server that is geographically closer to the website’s target market; for example moving from a US to a UK host, or from a single server to a global CDN.
Before and during the migration, there are a couple of actions which need to be taken in order to minimise downtime and prevent any loss of organic visibility.
Data & Configuration Migration
Before the domain is switched over to point to the new host, all website data and configuration files should be copied to the new server. This includes all pages and any product database, but also all additional assets such as images and CSS files, as well as the server configuration files. All currently existing 301 redirect rules should also be migrated and tested, as well as any firewall rules that allow access for external services such as a 3rd party database, Google Cloud or an Amazon Compute instance. If using HTTPS, the SSL certificate will also need to be reimported to the new server, or a new one purchased and installed to prevent any authentication issues.
DNS TTL Settings
The DNS Time To Live settings for the domain should also be brought down to a minimum before the domain is switched to the new IP address. This will ensure that the DNS cache servers are kept as up to date as possible to minimise any potential downtime when the migration begins.
Holding Page & Minimal Downtime
If any downtime is required during the migration to the new server, a holding page should be set up that returns a 503 HTTP response header. This will ensure that if the website is crawled by a search engine during the migration process it will be able to understand that the site is temporarily unavailable and to come back later to continue the crawl.
Post Launch Testing
After the site has been migrated and all DNS records fully propagated, a full test of the website should be run that covers both functionality as well as all technical facets to ensure that everything is working as expected.