URL Change Dilemma

Planning a major re-structuring which will change URLs

[notalian]

We have a large site with over 40,000 "generated" pages. We are planning some major changes in the code and database which will result in different URLs.

In the past we handled this by writing a custom asp error page that was able to direct the requests to the new URL. Now since the entire site structure has changed, it maybe hard on the resources to do that.

I am mostly worried about Google. When Googlebot visits our site after the change, will it make requests against what it already has in its database (in which case it will be sent to the new URL) or does it just re-crawl and does not care about what it had from the previous crawl? What about other search engines?

Any thoughts on above issue or related issues will be apprciated.

[trillianjedi]

I don't think that a custom script to automate the 301's to the new pages would be all that resource intensive, and you only need to run it for a couple of months.

Critical IMO. The bots will eventually re-index with the new URL's, but until that point, users clicking on your links in the SERPS will be served a 404. And that's not good.

In terms of the bots, you either need to 301 the pages to tell them that the page has moved permanently, or you need to just pull the plug on the old page URL's and let the bots index from scratch.

It will work either way, but I would always go the 301 route if SE referral traffic is important to you.

TJ