UPDATE 2009-05-21
I've been testing the #2 method of using a single network share. It is resulting in some issues with Windows Server 2003 under load:
http://support.microsoft.com/kb/810886
end update
I've received a proposal for an ASP.NET website that works as follows:
Hardware load-balancer -> 4 IIS6 web servers -> SQL Server DB with failover cluster
Here's the problem...
We are choosing where to store the web files (aspx, html, css, images). Two options have been proposed:
1) Create identical copies of the web files on each of the 4 IIS servers.
2) Put a single copy of the web files on a network share accessible by the 4 web servers. The webroots on the 4 IIS servers will be mapped to the single network share.
Which is the better solution? Option 2 obviously is simpler for deployments since it requires copying files to only a single location. However, I wonder if there will be scalability issues since four web servers are all accessing a single set of files. Will IIS cache these files locally? Would it hit the network share on every client request? Also, will access to a network share always be slower than getting a file on a local hard drive? Does the load on the network share become substantially worse if more IIS servers are added?
To give perspective, this is for a web site that currently receives ~20 million hits per month. At recent peak, it was receiving about 200 hits per second.
Please let me know if you have particular experience with such a setup. Thanks for the input.
UPDATE 2009-03-05
To clarify my situation - the "deployments" in this system are far more frequent than a typical web application. The web site is the front end for a back office CMS. Each time content is published in the CMS, new pages (aspx, ht