If you are interested in web site performance, you may be
interested in this short digression into server compression.
IIS 6 and 7, and Apache as well, provide the option to gzip
modern browsers know how to decompress those files. Compression can save you a
lot of bandwidth and download time. It is not uncommon to reduce file sizes by
way over 50%.
In IIS, compression is switched off by default for dynamic
files, such as .aspx files. This is because it increases the load on the CPU. However,
with the overabundence of CPU cycles on modern server hardware, switching on
compression for dynamic files on your server is almost always a great idea.
Also, IIS 6 and 7 allow you to set the compression level, so you can choose a
level that you're comfortable with. Finally, IIS 7 can automatically switch off
compression when CPU usage goes over a predetermined level (set by you), and
switch it back on after CPU usage has dropped below a second level (also set by
you). It even lets you cache compressed dynamic files, which makes compression extremely
Switching on basic compression on IIS 7 is easy, but getting
the most out of it is a bit tricky. Switching on compression in IIS 6 is just
tricky. Good places to find out more would be
(for IIS 7); and
(for IIS 6)
Or you could read chapter 10 of my book ASP.NET Performance
Secrets (https://www.packtpub.com/asp-net-site-performance-secrets/book) where
it is all spelt out in one place (believe me, this will save you a lot of