Results 1 to 4 of 4
  1. #1
    Join Date
    Dec 2006
    Posts
    30

    Unanswered: SQL Server upgrade advice

    Hello,

    I'm looking for wisdom from the experts regarding the best way to upgrade database servers.

    Here's my setup:

    Server 1:
    • Dell 2950
    • 146 GB SAS drive x6
    • 16 GB RAM
    • Direct-attached Dell MD1000 with 2TB SATA x6 for backups
    • Windows Server 2003
    • SQL Server 2008 Enterprise, using TDE


    Server 2:
    • Dell 2950
    • 146 GB SAS drive x6
    • 16 GB RAM
    • Windows Server 2008 R2
    • SQL Server 2008 Enterprise, using TDE


    Server 1 is currently the primary server, with several databases mirrored onto Server 2. My goal is to upgrade both servers to Windows Server 2008 RS and SQL Server 2008 R2 Enterprise with a minimum of downtime.

    How would you go about doing this?

    Thanks for any feedback!

  2. #2
    Join Date
    Jan 2003
    Location
    Massachusetts
    Posts
    5,800
    Provided Answers: 11
    If you all of your applications are mirror aware (a secondary server is defined in the connection string for Native Client), then this is easy. If you have a DNS name for the server that can be switched around, it is a little harder (you need to flush DNS in a number of places). If everything is going by netBIOS name, this will be difficult (all clients will need to be changed).

    An upgrade in place of a server that hosts mirrors of databases is possible. If you go this route, then the steps would be
    1) Upgrade mirror server
    2) break all the mirrors (very important)
    3) Point all clients at the new server
    4) Bring old primary server offline, and upgrade and re-establish mirrors.

    Like I say, if all of the applications are mirror aware, then this is easy. If like most applications, this is not the case, then you may need to visit each application server, and change configurations to point to a new name.

    Breaking the mirrors in step 2 above is very important, because (and I have some experience on this), the upgrade is a one way deal. You can not bring the databases up on the new 2008 R2 side while the mirrors are active, or you will likely corrupt the SQL 2005 databases. Why? Transaction log entries that SQL 2005 can not understand are now being sent to the SQL 2005 server. This will cause you a great deal of pain, if you decide to go back for any reason.

    There are a number of ways of doing this with DNS, as well. How much flexibility or tools do you have in this?

  3. #3
    Join Date
    Dec 2006
    Posts
    30
    Our DNS manager is in the office next to me, and all the clients are in the same building; no external access. The clients can also tolerate a small amount of downtime.

    Not all of the databases are currently mirrored, so your plan would seem to require either a) mirroring all databases or b) backup and restore non-mirrored dbs onto the new server, correct?

  4. #4
    Join Date
    Jan 2003
    Location
    Massachusetts
    Posts
    5,800
    Provided Answers: 11
    That is true. If the non-mirrored databases can take more downtime than the mirrored ones (which may be the case, since they are not mirrored), then you can do those first, since the DNS switch is likely going to be the key moment in the upgrade process.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •