I'm looking for a way to have several physical front-end servers with ACID data access.

In a setup where several servers gets load-balanced using DNS-round robin, the problem is that whatever server you land on the data must be ACID. E.g. when sharding data you need to have the shard-mapping ACID across servers, right? 

How can I achieve this using open-source software?

One solution is MySQL Cluster but Google or Facebook does not use this(?). Is there an alternative?


Question: User @include url Precedence over Script @include url
Answer: If the problem is include/exclude, you can override it with your own user preferences which stays on after script update.

Go to Add-ons - User Scripts ('Ctrl+ Shift + a' on Firefox)
Click on the Script's Option
Under User Settings Tab, Add Included/Excluded Pages that you want the script to run on
Click OK

More Info: User Specified Rules


  Since Greasemonkey 0.9.9, users have been able to specify their own
  exclude and include values through the script options dialog in the
  Add Ons Manager. Thus, each script has its own rules plus optionally
  the user's rules.
  
  The user's rules are checked first, then the script's rules are
  checked. If any exclude matches the page, the script does not run. If
  any include matches the page, the script will run. If a script include
  matches, but a user exclude also matches, the user exclude will take
  precedence over the script, and it will not run. If a script exclude
  matches, but a user include also matches, the user include will take
  precedence over the script, and it will run.


For example under Excluded Pages try: http://*