Length depends on the type of work you do.
If I wrote out my whole work history and education - nothing else - it would fill about 17 pages and that's just with each job taking up one or two lines - listing only year, company, prod name, prod type, job title
i now have about 5 CVs with all that divided up in to smaller categories, with lots of stuff edited out, so they're 2-3 pages now.
if you have only a few long term jobs then yes 2 sides is enough - but if its freelance and temporary jobs then you can have more - your industry will know this and understand.
its ok to go to 3, even 4 pages, - as long as what is on them is relevant to the job you're seeking, and not filler and waffle and spread out formatting
there are no set rules though so i would suggest you search online for current guides, with trusted companies - because everyone seems to have their own ideas of what is best and worst, and they often conflict with each other, which ends up causing confusion and worry.
trusted sites will most likely have done research and have a much more evidence at their disposal and are able to produce much more relevant advice gathered from lots of sources - rather than people on here who will generally only go able to by their preferences.