Disk I/O and ASPX Page Processing

[Guadala Harry]

Suppose two different servers (two different physical machines - no
clustering or farming going on here) on the same network:
1: Web Server (2003/IIS6)
2: SQL Server
.... and an ASP.NET Web application running of course on the Web Server.

The Web application serves up a product catalog (Catalog.ASPX); all the
data that appears on Catalog.ASPX page is retrieved at runtime from the SQL
Server database. Users can click a button in the catalog to request details
about any item in the catalog - and that detailed info is retrieved from the
SQL Server.

My question(s): In the above scenario, when is there disk I/O on the Web
Server? More specifically...
Is it true that, for a new Session, on the very first request of
Catalog.ASPX, the Web Server would *necessarily* read the ASPX page from
disk and then any code-behind logic processed?

What about on a postback? Suppose a user is viewing the catalog and clicks a
button that causes a postback - during which logic in the code-behind of
Catalog.ASPX causes additional info to be retrieved from the SQL Server and
sent down to the browser. During this Postback would there *necessarily* be
any disk I/O on the Web server to handle that request?

Would output caching Catalog.ASPX have the ability to completely eliminate
all disk I/O on the Web server for processing postbacks of Catalog.ASPX
within a Session?

Please note I'm not asking at all about disk I/O on the SQL Server in the
above scenario.

Thanks!

-GH

 

[Martin Dechev]

Hi,

Even if we suppose that everything is cached and served from the cache,
there will be still disk I/O operations - reading/writing the virtual memory
(the paging file).

Appart from this consideration, on each request for any of the pages (if
these are not served from the cache) the parser will need to read the file
from the disk (I'm not sure the .aspx files are cached by the runtime, but
even if they are, it will need to check whether the file has changed). So,
yes, there will be some disk I/O operations.

Greetings
Martin