Imagine a super librarian with an enormous brain (complete with wire rimmed glasses).
The super librarian can remember any page a user reads. Every word, every picture.
If another person asks for the same page – the super librarian says ‘no worries, and reads out it from memory’. If they haven’t read that page before, they can go get the standard librarian to get the book from the library (but they get busy with helping other folk), then the super librarian can read the page, and remember it.
now imagine there was 2 (or more) of those super librarians out the front of the library. If 1 of them ever saw a new page, they’d recite it so the other super librarians could remember it as well ‘hey Jim, just read a new page – have you seen this before ?’
Even if the library is closed, or on fire, the super librarians stand out front reciting pages and images – so the customer still get their pages.
Even if 1 of the super librarians doesn’t turn up to work (big night last night), then another super librarian takes over. Given they both remember everything that’s fine – customers can still get their pages read to them.
we have some tech in front of your WordPress website that remembers every page or image a web user clicks on – this is called a cache
we have a few of these caches, and they share any new pages/images they see
if the website breaks (error 500), or crashes, or is otherwise broken – we just give the web users data from the cache
if 1 cache blows up, or doesn’t have the page, another cache takes over (that’s why there is more than 1).
your website users always get a web page when they click on it
oh yeh, and it’s super fast, because it’s from memory/cache – it’s roughly 1000 times faster than a standard web server