What is the difference between site collection subsites and rootweb subsites?

Question

If I create site collection at http://server/sitecollection and if i create 3 sites:
http://server/sitecollection/site1 http://server/sitecollection/site2 http://server/sitecollection/site3

Are these sites subsites of the rootweb site or these are site collection subsites?

The reason that im asking is that im creating 10000 sites under http://server/sitecollection for a project that im working on. Time to create a site slowed significantly after i created 2500 sites. Now, im wondering if im missing something... or this behaviour is by design.

Any answers will help. Thanks

Answer 1

Site collections do not have parents, they are always at an equal level in a web application. The URL /sites/ is a managed path under which site collections are created, the 'root' of the web application is a separate site collection.

(you can create a 'portal' which creates a logical link between site collections but there is no true hierarchy created here, only clickable links in the navigation. site collections remain separate entities when you tie them to a portal).

There is no documented number to the maximum number of site collections, however if it's slowing down, consider putting some on separate content databases, as this will greatly help backup and recovery procedures.

EDIT: I didn't read that document well, the documented limit of site collections is 250,000 per web application, but I personally think this is a soft limit, and if you have problems over this value the first thing MS will tell you to do is to move some of the site collections to another web app.

EDITEDIT: As I've came across this confusion before, I've decided to write a blog post about this distinction. You can read it here.