Like the title suggests, I've bought myself a dedicated server and have 400+ domains I need to transfer over. This is my first time moving servers, so would appreciate any advice, feedback or pitfalls I should look out for. Many thanks in advance.
Hmm. If you want to avoid downtime, Setup all the accounts on the dedicated WHM ahead, and then upload all the files to the accounts, THEN transfer the domains. You can avoid ALL Downtimes by doing that. I've done it with several of my bigger sites.
Thanks Remotey for the great advice *green rep added. So let me make sure I understand this correctly: Download all files, up-load the new server before changing the DNS?
Yes, basically if you have the sites on both servers and then change the DNS, you should not experience any downtime. There may be a temporary problem with the mails as some of them may go to the old server but this should be for a very short period of time so it cannot be big problem. Just notify anyone using these accounts about the mail and that it Good Luck!
Yep you got it. Upload all the files / Setup each database before changing the DNS and you'll have no down time.
Really? Yep, good advice. Yep, you might also ask the new host to do the transfer. Many web hosting services can help you do the transfer. One more tip: Make sure you backup everything (remember to do that with emails as well). Add-on domains can be tricky, you might need to manually set them up - at least that's what I've been told regarding cpanel, not 100% certain.
If you wan't absolutely zero downtime, set up your DNS with a 3rd party now, and point it at your existing server. Setup the domains exactly as they are on your current server on the new server, and then change the DNS at the 3rd party DNS service. This way you aren't getting traffic to two servers at the same time, and you have no downtime. It also makes it much easier and quicker to switch servers in the future. With a low TTL, you can flop back the the original server if something goes wrong soon after switching. I currently use: http://www.dnsmadeeasy.com/, which isn't free but it allows you to set a really low TTL which is perfect if you are about to swap servers. Also, Dns made easy has name servers all over the country which is a much more reliable DNS system than having all of your nameservers on the same server / IP.
make sure that if you use linux on new server that your extensions match the extensions in the code. (CASE SENSITIVE)