Slide 89 of 111
For example, how many hosts are there on the Internet? How many of them have databases on them? Of them, how many have large databases on them? Now, sum the overall reliability across those relatively few machines with large databases.
Now, lets go back to the total number of hosts on the Internet ˇ how many do you think have filesystems on them? Pretty much all of them, right? Now, sum the overall reliability of those filesystems across all those machines.
Now, letÝs compare these two numbers. I submit that the overall total reliability of large databases is many orders of magnitude less than the overall total reliability of filesystems.