The Origins and Future of Distributed Computing and Clouds - The Practice of Cloud System Administration - page 451

Availability Requirements
For most companies, their Internet presence was initially treated in much the same way as
their key internal systems. They used server-grade hardware with some high-availability
options and additional capacity for scaling. For most companies, their Internet presence
was just another part of the infrastructure, and not a particularly business-critical part at
that. Under normal conditions the site should remain up, but system administrators could
schedule outages for maintenance as needed. Usually a scheduled outage for the web ser-
vice involved configuring another machine to respond with a static page letting people
know that the site was down for maintenance and to try again later.
Then new startup companies appeared with business models that revolved around con-
ducting business entirely on the web. These companies did not have existing products,
channels,andcustomers.Theywerenotadaptingexistingbusinessprocessestoincludethe
web.Forthesecompanies,theirInternetpresencewastheentirebusiness.Iftheirwebsales
channel failed, everything came to a standstill. They did not have the luxury of contact-
ing their customers to schedule a maintenance window, as they had no way to know who
their customers might be during that time period. Anyone with Internet access was a po-
tential customer. These companies needed a highly reliable Internet presence in a way that
noother companies hadbefore. Companies wanted 24 × 7operations with nomaintenance
windows.
Technology
During this era, home computers became more common, as did faster connections to the
home with xDSL and Internet service from cable TV companies. Better graphics and more
powerful computers resulted in better games, many of which were networked, multi-user
games. Voice over IP (VoIP) emerged, with associated new products and services. Disks
became larger and cheaper, so people started digitizing and storing new types of data, such
as music and videos. Inevitably companies built products and Internet services around that
data as well.
On the server side, companies looking to provide a more reliable Internet presence star-
ted buying RAID subsystems instead of plain disks, multiple high-end processors, and so
on.Whilethesetechnologiesarecommontoday,theywereextremelyexpensivethen.Ven-
dorsthatpreviouslysoldtotheverysmallsetofcustomerswhoneededeitherverylargeor
veryreliable computers hadanentirely newgroupofcustomers whowanted machines that
werebothlargeandreliable.SunMicrosystems'E4500serverwasthenormativehardware
of the dot-com era.
Loadbalancersalsoappearedonthemarketduringthisera.Aloadbalancersitsinfront
of a group of machines that are all providing the same service. It continually tests to see