You are probably deploying your CAS if you are a larger organization with specific needs. One of those needs is if you need more than 1 primary site because of geological/political issues. The version ( standard or enterprise ) of SQL that you might want to use on the CAS becomes very important if you are a larger organization.
If you use SQL Server Standard for the CAS, you can support up to 50,000 clients. But, if you use SQL Server Enterprise on the CAS, you can support up to 400,000 clients.
However you need to very well look at your growth plan because if you install SQL Server Standard on the CAS and then your company grows to 70,000 clients , you will have an issue.
You would say : “Why do I have an issue?“ , I just upgrade the SQL version on your CAS to SQL Enterprise to support those extra clients. However it will not work.
When the CAS is installed , it will be configured based on which target version of SQL is installed (Std or Ent). Once installed on SQL Standard, the table is a single partition, and will not be switched to multiple partitions when upgrading to SQL enterprise.
A CAS wipe and re-install is required to support more than > 50K clients and that will not be so easy or at least it will generate some additional problems.
Now you are might stuck about the question: “What about the SQL version on the primary sites ?” . Primary sites support up to 100K clients , but do NOT require SQL enterprise . SQL enterprise is only needed for the CAS if you need to support up to more than 50 K clients .
Little recap:
*CAS*
– Less than 50K clients –> SQL server standard is sufficient as long as you are not going over the 50K limit (Upgrade to SQL enterprise is NOT working when crossing the 50K limit)
– More than 50K clients –> SQL server Enterprise is needed.
*Primary Site*
– SQL server standard is always sufficient !
Hope it helps ,
Kenny Buntinx