i am little bit confused that i have set my Google crawling rate by default. and Google crawl my website with in 2-3 days.i want to change Google crawling rate in webmaster tool. my website contain 20,000,00 pages but present Google crawl only 3,000,00 pages only. if i increase crawl rate then my pages will crawl fast or which crawl rate will be suitable for my website. i am waiting for replay
I can tell you that I tweaked the crawl rate for my website in GWT but this did not impact the number of indexed pages. Currently I left it to recommended.
Wow, you have 20 million pages on your site, and Google indexed 3 million of them? That's quite a lot... From my experience, changing that doesn't really effect the crawl rate. However, you seem to be in a pretty good state if you have 3 million pages indexed. I wouldn't worry about it, just wait, over time Google will probably index the rest of the pages.
Crawl rate refers to the speed of Googlebot's request during crawl process.... It doesn't have any effect on how often Google crawl or how deeply we crawl your URL structure. Source: http://www.google.com/support/webmasters/bin/answer.py?answer=48620