|
Businesses rely heavily on email for central business processes like customer transactions, vendor relationships, and internal communications.
The email approach approach to high availability popularized by Google: large numbers of computer servers built on commodity hardware. The basic theory is that server failures are common, so arrange servers in pairs or clusters, then build failure detection into the network or the software.
In the past, we have tried the more traditional, high availability design approach: high-end servers with high-end disk subsystems. The mean time between failure (MTBF) was only somewhat better than commodity hardware, although the high-end server hardware was many times more expensive. For the same cost, key services are now spread across large numbers of servers in single-purpose clusters. Our experience has shown this greatly reduces the risk that any service might become unavailable to our customers.
|
