Explanation for CMDB relationship between Server and Database?

[Deepak Ingale1]

Hello,

Can someone help with business case and example to understand below two type of relationships between Server and Database

Also, I am confused between the CMDB class "Database Servers" and "Database Instance" since I am not sure what exactly database instance refers to.

How relationship can be established between these different classes like Server, Database Server, Database Instance.

[Mike Allen]

A server is a physical construct.   You can choose to make it an app server, or a web server, or whatever.   The first relationship is just that representation of you deciding to make that server a database server.

I am assuming that the second relationship is defining the logical server (as in, UNIX server or Windows server vs. HP server or Dell Server) with the logical database that is running on that server.

A database on a server can have multiple instances, slivers of that database.

* Database: A collection of physical operating system files or disk.

* Instance: A set of background processes/threads and a shared memory area, which is memory that is shared across those

threads/processes running on a single computer.

[Deepak Ingale1]

Hi Mike,

Thank you for your reply. It was helpful.

Now if I have to decide the relationship of my Server with database, should I use "Server Hosts Database" relationship or "Server Runs Database" or both are one and the same?

Can I get some business examples between relationship amongst Database, Server and Database Instance?

Demo data available does not have any sample "Database Instance" record to understand how those are related to each other.

[Mike Allen · Accepted solution]

OK, let's say you have two applications and each application needs access to the database.   However, each application is very strict on which patches can be installed on the database.   Let's call them app_one and app_two.

Now, let's say, in this hypothetical world, you have only one server on which to install the database.   Let's call this example.server.com.   example.server.com runs Windows 2008 R2 Datacenter.

You look at the databases software out there and decide on MSSQL.   You decide that you want to turn example.server.com into a database server, so you install MSSQL on the server.   You have to name the server in the install.   You name it MyDatabase.server.com.   You now have MyDatabase.server.com that is hosted on example.server.com.

You have two applications, each with the need to have different patch levels, etc.   You create two named instance, app_one_instance and app_two_instance.   Each now Run On MyDatabase.server.com, which in turn is hosted on example.server.com.

Now the apps can connect to their databases.   These apps depend on their instances be up and running.   In the end, you have something that looks like this:

[Deepak Ingale1]

Excellent Mike, it can not be more explanatory than this.

Thank you very much for demonstrating this up.