Got Sitemap Running - A Few Questions.

I have had this running now for 2 days and I have a few questions which I'm hoping someone can help with. My site has 3.5 million posts, 336,000 threads, 38,800 users, and vBSEO is also running.

1. In the "Sitemap Generator History" I now have 2 instances. Both have 4.2 million URLs and took almost 5 hours to run (each). Settings are "Max URLs in Sitemap Files" 20,000 and "Delay Execution After Each Sitemap File" is 60. Does this sound right? I thought is would only generate changes each night, not generate the whole lot each time.
2. How would Google deal with a sitemap with 4.2 million URLs?
3. How long would it take Google to index this lot, and would it start with the oldest or newest first?
4. Do the old sitemap generated files in the "data" folder become redundant after a time and if so, do they get deleted automatically?
5. It is worth turning off "Include Show Post Pages", this is currently turned on.
6. Is there a hack to get this to work with Photopost?

Any help would be great. Thanks!

Mike

Hello,

1. Sitemap is re-generated every time it's executed.

2. Sitemaps protocol allows up to 1,000 sitemap files in index with 50,000 URLs in each file.

3. That depends on many factors, but Google tends to index fresh content faster as far as I can tell.

4. Sitemap files are overwritten with new data.

5. In case if you have "Replace showpost with permalinks" option enabled vBSEO CP, you should disable "Include showpost URLs" setting in sitemap generator options.

6. You can get it here: Sitemap addon for Photopost and Photopost Classifieds