| Re: PB dns avec plesk aprés migration |
Titre du sujet : Re: PB dns avec plesk aprés migration
par seboseboss sur 23/08/2008 15:03:59
Voila ce qu'il aurait fallu que je trouve en frncais pour m'en sortir.il y a bien une propagation dns meme si l'on garde les meme seveur dns,et tout ce passe graduellement:
Mintenant c'est trop tard pour moi j'ai plus qu'a attendre la propagation,mais peut etre ca servira a quelqu'un;
What other problems are there with a Migration?
There are a number of steps that we need to go through when performing a migration:
* Select the domain(s) to migrate and run;
* For each domain successfully migrated, reset it's DNS to the default values for the new server (updates it's IP address);
* On the old server, change the DNS settings on the domain from Master to Slave mode, and point it at the new server;
* For domains which we are the registrar, update it's name-servers to point to the new server (note that if we are not the registrar, you will need to do this yourself); and
* Wait for propagation and then shutdown the domain(s) on the old server.
Once the migration has been completed, everything else is associated with the domain's DNS (updating the records to reflect it's new IP address, & changing the name-servers), and due to the way DNS works around the Internet, these changes are not immediate.
How DNS works and why the propagation effect exists is covered in detail in the following Knowledgebase article:
* Why does a change to my DNS take so long to appear?
For all our servers, the TTL for our DNS is 4 hours, so there will be a 4-hour window where both servers are dealing with requests for the domain (the progression is gradual, with more requests going to the new server as we move closer to the end of the 4-hour window).
However, before the new server can begin to take over, the name-servers normally need to be updated to redirect all new requests to the new server, allowing the new DNS records to be returned. This change alone can take around 24 hours to complete. Therefore, to overcome this, we set the domain's DNS on the old server from Master mode (it set's the records and replies to requests with them) to Slave mode (it picks up the records from another server and responds to requests with them instead).
This eliminates the propagation effect for the name-server change (even though the change is still taking place) as both servers will now be replying with the same data. It therefore doesn't matter which server you are talking with, reduceing the main propagation window to no more than 4 hours (the time it takes for the actual DNS records to expire).
We will also (unless specifically requested) only perform a migration in the early hours of the morning when the servers and the sites are at their quietest (as most people are asleep). This minimises the number of requests your site will handle, and by the time people wake up and/or return to work, the site will be running on the new server.
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