Redirecting 5% of site traffic for test.best way to do it?

[MisterT]

if i wanted to redirect about 5% of my site's traffic to a subdomain to do some testing on it (like beta.domain.com instead of domain.com)...do you know the best way to redirect that traffic and get penalized in the search engiens? i would nofollow the beta.domain.com too of course...but what type of redirect and such is best as a general rule?

[caveman]

Why are you using a subdomain for this, as opposed to just dynamically serving up different content? A/B tests are pretty common.

You could just use "IP delivery", exclude the bots from traffic sent to the beta (if the beta is different enough to worry about). If you use a subdomain, I'd also exclude the bots from access to the beta subdomain via robots.txt.

What you don't want is for the bots to index the beta page. Could be dup issues depending on the content, and certainly competitive issues.