We’re told it’s the most stressful thing that you can ever do. Indeed, it can seem such a monster that people who should know better put it off for years. Never has the old and familiar exerted such a magnetic pull on your heartstrings as when you have to say goodbye for the final time and move on. However, now that you have finally decided to migrate web servers, be bold, take the bull by the horns, follow the simple advice in this blog and everything will be just fine. Emails will find their way to their right address, nothing of value will get lost, and you will only have a few more grey hairs than you do right now.
So, that said, are you sitting comfortably? The first thing to do is prepare your DNS (or Domain Name System). Now, the DNS cache has been a very useful innovation, providing a database of all recently visited domains. However, it’s based on your IP and this will change now with your new server. This can take up to seven days on the net, so make sure you change your DNS TTL – Time To Live - which dictates how long the cache saves addresses for. I’d recommend doing this at least a week before the big day. By the way, remember to change any SPF – Sender Policy Framework - records you may have at the same time (we do love our acronyms in computing, don’t we!).
Once that’s done, you can start to set up your server/servers. Do they have the right OS installed? Do the servers and other hardware meet the criteria for the apps that you want to run? How do you want to allocate IP addresses for your web site?
Next it’s time to tune the new server or servers. Is the file system in order? Are the partitions appropriate? In practice, your host will probably set up RAID – Redundant Array of Independent Disks - and partitions and test them for you.
Then install any security measures you require, before you go further. It’s much easier to do this before there’s any content on the servers. Think of it like decorating – life’s a lot easier if there’s no furniture to get in the way!
Once the security’s sorted, the stars of the show can then move in – the applications! And the supporting cast of software they may need to make them look good. If they're web servers, test they’re all fully functional with a sample web page.
That other star turn, the data, is next in line. How you migrate data depends on the type of data and the servers you have. Static data is likely to be relatively simple, maybe with the help of a synchronising tool such as rsync. A complex database, on the other hand, will need a comprehensive backup and restore regime. Whatever the case, it’s always a good idea to do it when the office or data centre is quiet. Work out how long this task is likely to take, then plan accordingly. And err on the side of caution with your estimates. Once the data has been moved, test at your new IP address.
You’re getting there! N you can pick a date to make an honest woman/man of your server to be and go public. Those DNS changes we discussed should have kicked in after a few days, and then you’re ready to roll. Set a maintenance window to take down the site from the old server/servers. Migrate database and data changes, and confirm they’re working properly with the IP address, changing DNS records to resolve new IP address.
Then redirect traffic to the new servers. Now you’re really ready to rock, with the latest data and traffic with current DNS info going straight to your new server.
Finally, all that’s left to do is to enable automated site maintenance tasks from the old server and change TTL values to default. Restore your SPF record when it’s confirmed that the internet recognises the new IP address.
And that’s all there is to it! If you've got any server or network documentation written, it's a good idea to update it.
Of course, guidelines such as these are inevitably a bit one-size-fits-all, and there may be scenarios where modifications are needed. For professional advice about all issues regarding servers, call King of Servers on 0845 611 8696 or email sales@kingofservers.com.
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