SQL - new server - use a subnet?

  • Hi,

    In the process of upgrading our old SQL server hardware.

    Running into issues were we have years of development that references old SQL server by name. We have webservers, hundreds of SSIS packages, old ODBC clients, etc..that all reference this old server by name. To make matters worse there are some old client server apps that we don't have access to anymore (complied exe's).

    I had a previous thread on here and it was recommended to use a CNAME change (thanks guys). I have started testing with that but I'm finding it is not working for all our various scenarios.

    So, wondering if it might be easier to have sys admins create a new subnet?  I would create a new sql server in the new subnet that is an exact mirror (including instance\server name) of our current production sql server. Restore backups, SSIS, SSRS etc. Then when we go live, switch the old server to new domain and then bring the new server into the existing (old) subnet. The old switch a roo.

    We really don't have the staff to go and change every object to a new server/instance and the amount of external objects that are referenced is in the hundreds. Starting to feel like something might be missed by using the CNAME change. But if we can create the new server in a different subnet that is a exact mirror - that might be the only was to assure we don't miss anything.

    Is this a decent plan? Or am I missing something where this hair brained scheme wont work as I expect? Would subnets work? Would it make more sense to create a brand new dev domain and then a trust between the domains?

    • This topic was modified 1 month, 4 weeks ago by  krypto69.
    • This topic was modified 1 month, 4 weeks ago by  krypto69.
    • This topic was modified 1 month, 4 weeks ago by  krypto69.
    • This topic was modified 1 month, 4 weeks ago by  krypto69.
  • The CNAME should work for all scenarios as it's just a pointer to the true A or AAAA record in DNS.

    What specifically isn't working when using the CNAME in the places it is failing?

    Additionally creating a clone you would have to give it a different name at first as you cannot have the same NetBIOS name in AD it just wont let you.  So you would have to do a NetBIOS rename and then an sp_dropserver/sp_addserver combination when you rename the new machine into the old machines name at migration time.

  • There's nothing that should prevent a CNAME from working.

    Also, it's not that difficult to rename a server.  You would need to remove the existing server from AD, rename it and re-add it to AD (assuming that you need to do that) and rename the new server to the old server.

    Michael L John
    If you assassinate a DBA, would you pull a trigger?
    To properly post on a forum:

  • There is more than one way to switch a roo.

    Renaming servers the way to go but the roo you switch first should be your existing server name. When you change its name create a DNS alias with the old name of the server and point it to the new server name.

    You now have a layer of indirection between the connection strings and the server they refer to. This will allow you to build a new server, populate it, and cut over to using it without any further connection string changes. This would mean your original server name lives on indefinitely as an alias name, but its target can be changed as often as you wish.

    PS Please remember to test this on some other servers, even if you have to build them (as hyper-v guests of course). When you have practised it you will know what to expect when you do it on you live server.

    • This reply was modified 1 month, 3 weeks ago by  EdVassie.

    Original author: https://github.com/SQL-FineBuild/Common/wiki/ 1-click install and best practice configuration of SQL Server 2019, 2017 2016, 2014, 2012, 2008 R2, 2008 and 2005.

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