all of our racks don't really look like a traditional server rack these are custom designed and built for Google so that we can optimize the servers for my proficiency and high performance computing is true that sometimes drives fail and we have to replace them to upgrade them because maybe there is no longer a mission to write we have a very thorough and chain of custody process for managing those dries the time to their checked out the server to their brought to a halt for secure change where there are racist and crushed if necessary