We have a server running single instance of SQL SERVER in production environment.

We are planning to create another Instance of SQL SERVER in same server.

My question do we have to buy a new license or the existing license is good enough ?


You can install as many instances of SQL Server as you like on a server, up to 50. The licensing is by the server, not by the instance (it used to be, once upon a time) so you have some freedom to do so.

The real question I would counter with is: Do you need another instance? Most people don't.

  • We have both UAT and Prod in single server. Load on UAT should not impact the performance of PROD. So we plan to split UAT and PROD into two different instance so that we allocate even amount of resources(memory) to both UAT and PROD. Is this a correct approach ? Actually this is my real question and problem – Pரதீப் Dec 26 '16 at 6:34
  • Well, there will be a perf impact if UAT ever does actually start to use load. I would prompt you to install the developer edition on the UAT server and set up another UAT server specifically to keep the databases separate. I don't believe that using developer edition violates the TOS for UAT, but I would need to defer to one of the other site SQL Server experts to make sure of that licensing question. In this case, I would think it's acceptable, as it is for development and not for production usage. – jcolebrand Dec 26 '16 at 6:36
  • 2
    "Other than this is there any other problem I should be aware of?" - Consider CPU, disk usage, disaster recovery (DR), the high likelihood of accidentally deploying data or code changes to the wrong environment, eg data fix to live you were meant to test in UAT. – wBob Dec 26 '16 at 7:52
  • 3
    Have you heard of Azure or AWS? Consider creating your non-production environments in the cloud. It could potentially be quite cheap, avoid overload on your server, maintain a healthy degree of isolation between your environments and prevent any unintended consequences. The elasticity of the cloud will allow you to power down your environments when not using them, thus not incur additional cost. – wBob Dec 26 '16 at 7:55
  • 1
    Disk usage as in disk contention. Imagine your UAT instance pulls a big read from disk during a peak time in prod. Similar for CPU. If these were virtual machines on a single host, you would at least have some control - but it's still not advisable to have these two critical services on the same box, it's too risky. What are your approaches to High Availability (HA) and Disaster Recovery (DR) in this setup? – wBob Dec 27 '16 at 10:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.