wpDone Cache keeps your WordPress website running no matter what

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.

What really happens

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

What our customers need to know

• this is super smart, and will keep your WordPress website running.
• you don’t need to do anything extra. It’s just WordPress as normal for you.
• if the source WordPress website is broken pages and images (and css/js etc) will still be delivered to end users. But form submission (like contact us, or shopping carts) doesn’t work until the source website is fixed.
• you don’t have to make a support call. And if it’s your customer’s site – you don’t get them ringing you up either
• If you log into /wp-admin/ (WordPress dashboard) then your session bypasses the caching, so you can see that actual website so you can fix any problems.

For technical geeks (in geek speak).

• we have a cluster of varnish caches. The varnish caches are replicated and synchronised  – copying pages/images between each other.
• varnish has been customised for WordPress, and for the situation where the WordPress web server returns error 500 we return a cached page instead.
• we use a haproxy as a load balancer on top of varnish. haproxy checks which varnish caches are healthy, and makes sure each web request get’s to a running . haproxy also handles the https certificates.
• we use keepalived to float the real IP address , so the real IP address is co-located with a running haproxy load balancer server.
• Your WordPress website can failover to any of a few load balancers and varnish caches. No DNS changes are required. The failover less than 2 seconds.

By Scott Farrell on January 22nd, 2017 , Follow @scott_WordPress Tweet to @scott_WordPress