I just bought myself a dedicated server and already have 2 other VPS on different providers. I have a small 1 GB single core with 4 ips and 25GB storage VPS A 2 GB twin core with 3 ips and 50 GB VPS and now the new 8 core 4GB, 4 ips and 500 GB RAID Dedicated Server. All systems run Centos (2 x v7 and 1 x v6.5) (The VPS running V6.5 will be updated to V7) The 2 old VPSs are setup in a small cluster for the DNS etc I am thinking of instead of hosting sites on all of them, I would rather have the dedicated as the main hosting and use the VPS for seperate Mail, DNS, backup etc I am looking for some ideas and info regarding th best way to go about this, remembering that the 2 VPS are currently hosting a few sites that I'll need to move. My main aim is for security and performance. My thought at this stage is transfer all to the dedicated then then setup the 2 VPS for their new roles and then link all as required. Anyone done similar of is their any tutorials on muti server setups etc.?
In my opinion, the DNS routing will be the biggest issue you have with multiple servers. As you transfer around domains, you need the DNS to update to find the new IP.
My opinion would be to setup the Ded as your main and transfer the sites there. Then use the 2 VPSs as Name servers. I am assuming you have your own name servers. Best is if you can keep the name servers clean and only of that. Keep the TTL low ... 300.
This is what I have done. Though I am still in the process of transferring hundreds of accounts from cPanel.....!
As you hosting needs expand, you can just add more servers. Again, my opinion is I would prefer several smaller servers than one large one. The servers only need to know about the name server, not each other. Better security. And very easy to transfer domains between them.
Then its a matter of setting up a DNS cluster for each new machine - in your case one one - to update the name servers as new domains (cirtual servers) are created.
[Ideally i would like to integrate a 3rd part DNS API like Vultr, et al. to manage my DNS and hook in an API call via a plugin. Then all three of your servers can be VirtualMin and have hosting accounts and all independantly updating a separate DNS .... but I haved not solved that one yet!]
Use S3 or DO Spaces for backup. ie not in your hosting infrastructure.
This is how I do this. https://www.virtualmin.com/comment/801713#comment-801713
My first Virtualmin server is NS1, and I have two Webmin servers as NS2 & NS3. NS1 is master DNS server to the first Virtualmin server, and slave to the other Virtualmin servers. NS2 & NS3 are slave to all. When I create a new virtual server on any Virtualmin server, DNS is set up correctly on NS1-3 automatically. DNS managed on any Virtualmin server is propagated correctly.
You don't need to use my structure above. I only use Virtualmin on NS1 because it was there when I set up everything else. It's on my todo list to make all the public DNS servers slaves to the Virtualmin servers and not have Virtualmin servers answering queries.
I am thinking along those lines of having the smaller VPS as simply a DNS and the larger VPS as DNS and possibly host my own smaller websites. Leave the Ded Server as main host and work horse. I thought 2 of separating the database but may leave that to if, and when, I get a secondary Ded and possibly remove the small vps. Depends on performance overall.