Thanks very much for your valuable input. We are serving our static content from sub domains and having cookies set up at the domain level . We do need cookies at domain level and can't get rid of these.
I made a cookieless subdomain, the server is lighttpd, so I put a .user.ini with session.use_cookies = 0 inside, put all my images in there, but I had no gain in pae load. Also the static content of subdomain did not load simultanuasly with main domain content, but after it like it was when all content was in main domain. In other words, nothing has changed. But I see the static content I defined (images) being served from subdomain.
Did I do anything wrong?
Do you have a link to some test results? Using a separate subdomain will not make the browser increase parallelism if it is being blocked for other reasons (only if it has maxed out it's 6 connections on the main domain).
Just removing the cookies themselves is mostly a rounding error for sites unless they have enormous cookies and a huge number of requests so I wouldn't be surprised to see no impact from that.
Yeah, you have few enough resources that the DNS lookup time for the separate domain is using up any benefits you might see from sharding (and you have so few resources that sharding won't help anyway).