Discussion Coping with Failures
◼ 4 disks/server, 50,000 servers
◼ Failure rate of disks: 2% to 10% / year
◼ Assume 4% annual failure rate
◼ On average, how often does a disk fail?
a)1 / month
b)1 / week
c)1 / day
d)1 / hour
50,000 x 4 = 200,000 disks
200,000 x 4% = 8000 disks fail
365 days x 24 hours = 8760 hours
