You can set the rate at which Googlebot crawls your website in Google Webmaster Tools.
This is how you should limit Googlebots access not by denying it access. Because noindex pages they will still visit causing hits on your server. Robots.txt disallow may work but be careful you correctly edit that file. nofollow is only Good for one specific link. If you have a link to that page in your sitemap they'll still crawl it.
Crawl rate refers to the speed of Googlebot's requests during the
crawl process. It doesn't have any effect on how often we crawl or how
deeply we crawl your URL structure. If you want Google to crawl new or
updated content on your site, use Fetch as Google instead.
Google has sophisticated algorithms that determine how much to crawl
each site. Our goal is to crawl as many pages from your site as we can
on each visit without overwhelming your server's bandwidth.
If Google is crawling your site too often, and slowing down your
server, you can change the crawl rate (the time used by Googlebot to
crawl the site) for sites that are at the root level—for example,
www.example.com and http://subdomain.example.com. Changing the crawl
rate can cause some problems (for example, Google will not be able to
crawl at a faster rate than the custom rate you set), so don't do this
unless you are noticing specific problems caused by Googlebot
accessing your servers too often.
You can't change the crawl rate for sites that are not at the root
level—for example, www.example.com/folder.