"On which" or "upon which"

Today, I am writing technical documentation that instructs the user how to install software to a server. I encountered the following sentence and am unsure which is correct:

When installing to a server other than that on which SQL Server is installed, ...

Should on be changed to upon?

When installing to a server other than that upon which SQL Server is installed, ...

It all seems like a mouthful, but appears to be grammatically correct.

Both are indeed acceptable. I agree with Peter that upon kind of reminds me of something being within a physical relativity of the SQL server which is something I do not think you wish to convey to the user.

However, I would write

When installing to a server besides the one on which the SQL Server is installed …

instead of

When installing to a server other than that on which SQL Server is installed …

(Little late, but for the record ...) The best way to figure it out is to rephrase the clause as a sentence, i.e.:

SQL Server is installed on another server.

Using "upon" in that sentence would sound stilted.