Symptoms

Client had a question regarding upgrading two servers that use the same SQL database.
Can we take 1 server offline and perform an upgrade, or will the installation process affect the database to the point where the entire environment will be unusable until both servers are at the same version?


 

Diagnoses

If you upgrade one server at a time, it will leave the other server unusable. What can happen is that while upgrading Server A, the database will be upgraded as well. Since Server B is using the same database, when it tries to connect/query the database it will generate errors.
We would recommend upgrading both servers at the same time so that this can be avoided.
 

Resolution

Both servers need to be upgraded at the same time to avoid errors.