Hello, almost all answers to your questions are well detailed in the documentation.

i don't know the exact amount of links on your site, but if for example you have 150.000 links generating a whole sitemap in a single operation will result in a server error. This is normal because the script timeouts thus you receive the error.

For this reason JSitemap has the precaching AJAX generation to generate by steps giant sitemaps. This is explained in the PDF docs at the paragraph 'Precaching and AJAX generation'.

If your final sitemap exceed the Google limit fo 50K links the sitemap must be exported as a splitted sitemap, and then submitted the sitemap XML index. Read the PDF docs at the paragraph 'Sitemap splitting'

Thus the correct steps are:

1. Generate the full sitemap with AJAX precaching
2. Export it with the splitting enabled
3. Upload all the chunks (XML files) to your server and submit the XML sitemap index to Google

We have generated sitemaps with 500.000 links with this technique, then splitted and exported in chunks of 40.000 links.

Optionally you could opt to use a cronjob to generate a big sitemap. This is explained at the paragraph 'Cronjobs usage'

NOTICE: the data source for your Kunena forum topics must be enabled only for XML sitemaps and excluded from the HTML one. It's not possible to include so many elements in a browser window.

Best regards,

John