Is there a way to move an entire server of clients over silently so clients wont know they were moved. (no downtime or at least no one having to update their dns info at the registrar to point to my new server info)

Essentially can I set the old nameservers up on the new server and just have Cpanel pull all the site over? I know i need to change the IPs associated with the name servers at my registrar level but other then that what all I do i need to do?

There is 50 sites and only 1 has ssl , any details on the smoothest method would be appreciated.

cPanel has a pretty good migration utility.

You listed everything. I can't think of anything else necessary.

My opinion on the smoothest transition would be to migrate the data. Next, use your hosts file to verify that each site works. Then start moving the DNS over.

If possible, set the domains TTLs low before the migration to minimize the time that the old dns records are cached.

If you have sites that access mysql, open mysql port on new server to old server through firewall, add old server to allowed mysql hosts in cpanel, move the database over to the new server, then immediately edit the config file on the old server to point to the new server so if someone hits a dynamic site on the old server due to cached dns their posts, etc. end up on the new server during the x-hours of propagation. (only problem will be if you have dynamic sites that upload contents to the file system; for these sites you might setup as ip based and put an .htaccess redirect on the old server that directs to the new ip for no downtime/no content ending up on the old server during the propagation period.)

Also if I have accounts with more than 1 GB of files and emails per, I don't use the direct server to server import in whm; I move the daily backup folder to old-daily (just because I like to insure a fresh full backup), perform a full cpanel backup, manually move the backup to the new server, and then restore multiple accounts from the backup.

well i guess my biggest requirement is no sites can go offline or these clients will leave in droves.

I checked and every site is under 500 mb. Im going to start moving the data over now using the cpanel multi move function. So once the data is moved over , and i see via ip address that the sites load, mysql dbs are in place what is the next step.

I would assume I could go into the new server and put the nameservers but ill then have 4 nameservers on one server? is that ok? right now i have clients setting sites up at ns1.newservername.com and ns2.newservername.com
if I had more nameservers it will be ns1.oldservertitle.com and ns2.oldservertitle.com , can the server handle and sort all these namservers?

then do i goto the registrar and change the ips associated with the nameservers to point to the free ips i will set for nameservers above??

I think i need a tiny step guide from "the data is set on the new server" these clients will eat me alive.

I don't believe it causes any extra load on the server to listen to additional "old" nameservers set to additional IPs vs. serving the same domains pointed all to the same new nameservers. That part is no problem. One very minor note is that cpanel now allows the option to use your default nameservers or the ones defined at the registry for the domain when creating an account; I'm not sure if this option exists when importing/restoring multiple sites... if not you want to set the nameservers on the new server for each old domain to match what's defined at the registry for the old domain or it will look ugly when someone queries a site like dnsreport or intodns.com giving error messages re: stealth nameservers (though it will still work ok.)

hmm ok so the data has been moved, all sites including ssl certs and mysql dbs - everything is set and working fine.

how do i setup 2 additional namservers on a server that already has its name servers setiup in cpanel..so that the new server becomes the host/nameserver for all these 50 sites I moved over (that are still point to the old namserver/dns at each of their regsitrars)?

Lost on the next step above.

If I remember correctly by default on a cpanel/whm server bind/named listens on all ips on the server (double check the named conf to confirm) so all you need to do is to change the ns1.oldserver.com and ns2.oldserver.com nameservers defined at your registrar to two other IPs on the new server (could even be the same ips as ns1.newserver.com and ns2.newserver.com with most registrars now I believe, though I prefer to use a different IP for each nameserver to be "oldschool" proper.) That should be all that is necessary. Also, I would check a domain transferred from the old server on the new server (edit dns zone though whm) and see what the nameservers are defined as; if ns1.oldserver.com and ns2.oldserver are set for the old domains at their registrars these should be set in your dns zone for the domains not ns1.newserver.com/ns2.newserver.com unless you plan to change them over at the registrar; otherwise you'll get stealth nameserver warning which look ugly to someone checking even though that will work ok too in practice.

wow the new server had the hardrives reversed so i had to reload the os. what a bummer for a new server that was already 'late to live'.

For the server move i (regrabbed all the sites via cpanel transfer) smoothly as butter.

I went into the registrar as you stated and changed the old servers name server ips to 2 old school unused ips just for these "carry over" namservers (on the new server) and left the new namservers for current sites on the new server alone. So far it looks smooth I see the namservers have updated i just dont see any sites popping up yet when i test with sitename/cpanel so I guess ill give it more time? Any better way to check what site is pointing where? I use whois.sc and it seems to be slow/outdated for dns/ns live.

My last concerns : will any sites see downtime during changeover for over an hour or more If i have the old and new servers hosting the same sites ( i figure ill leave the old server up a few days)

Jeff and others thanks! So far it seems like a "noob" proof plan.