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So, file server migration.

I've robocopied everything over and kept folder permissions intact, I have recreated the shared.

My question is I need a transparent way of switching all the users from the old server (GB-LON-FS1.domain) to the new server(s) GB-LON-FS4.domain.

people have to be able to access the files via \GB-LON-FS1...

My initial plan was to change the dns record for GB-LON-FS1 to FS4's IP address however I realise some users will have the old server's IP cached.

My other thought was to change FS4's IP to that of FS1 and leave the DNS alone.

Would there be issues with UNC paths if the server's hostname does not match the dans entry? I don't assume so.

Can you think of a more transparent way of doing this? All old UNC paths must remain the same. I would prefer to leave AD as is but let me know if hostnames have to change.

I also have FS3 which is DFS replicated from FS4, would it be worth adding two DNS records for FS1 and round robbining it or would there be issues.

ZZ9
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  • `My initial plan was to change the dns record for GB-LON-FS1 to FS4's IP address however I realise some users will have the old server's IP cached.` DNS records aren't permanently cached. If needed, you can flush them on the client by running `ipconfig /flushdns` from a command pronmpt. You can accomplish your goal by simply creating an A or CNAME record in DNS for the old server that points to the new server and disabling strict name checking on the new server. – joeqwerty Feb 01 '15 at 17:09
  • I am aware of flush DNS, however this is not realistic on this scale. If it were only 25 or 50 users, then fine. Not 1000+. Someone, somewhere will have stale DNS records. – ZZ9 Feb 08 '15 at 02:23
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    The default TTL for DNS records when using the DNS Server role in Windows server operating systems is 1 hour. I hardly see how this is going to present any problems if you schedule the change during a maintenance windows or during a period of light usage. – joeqwerty Feb 08 '15 at 03:09

1 Answers1

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This can be done and I have done that before. You can access a share with a random DNS name pointing to your server even if it is not the Active Directory name of the server.

Obviously you will need a small down time to do this. Ultimately, to avoid this kind of issue in the future, you want your user to access file server resources through an abstraction - either through a different name or using DFS.

So from memory, the procedure is:

  1. Set up all the same share on the new server.
  2. Turn off all the shares on the old server, disconnect all users from it.
  3. Do a final copy to make sure that the new server has all the up-to-date files.
  4. Remove the old server from the network.
  5. Delete the DNS entry for the old server (remove from AD also).
  6. Make a DNS alias entry for the old server name pointing to the new server name.

If you want to avoid the DNS caching problem, then a few days before doing the above, you can change the DNS TTL so that the refresh occurs faster when you do the change. Depending how many computers you have, you could also use PsExec and do a DNS flush on all machines.

But I'll repeat again because this is key for your future. DO NOT set things up so that users end up with shortcuts or bookmark to a server name. Use aliases for services. (Ref.: The Practice of System and Network Administration by Thomas A. Limoncelli - and probably many other references).

ETL
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