Home Is Home: The Physical Practicalities - Smart Home Automation with Linux and Raspberry Pi - page 127

You might consider a separate file server whose sole job is to provide files for the rest of the house. In this way,
it can be stored in a physically secure location (hidden out of sight, perhaps in the loft or attic) to prevent precious
data from being accidentally destroyed or stolen. Securing the server in a solid rack also helps prevent against theft,
because no one can easily walk off with a Backblaze Pod
( http://blog.backblaze.com/2009/09/01/petabytes-on-a-budget-how-to-build-cheap-cloud-storage/ )!
Bandwidth Capabilities
This is generally a nonquestion, as the current crop of network cards are all support at least 100 Mbs (with most
supoprting 1000 Mbps without batting a silicon eyelid), which is fast enough to distribute several movie streams
around the house. The modem speed will usually limit your external streaming capabilities, but so will many other
factors such as broadband contention in your area, current network traffic, and the target machine and its LAN.
Unlike corporate servers, most home servers can suffice with only one network port since a decent stand-alone
router can perform most of the necessary filtering and configuration tasks that often need two Ethernet sockets.
However, any future upgrades to your machine (such as moving the firewall software to the server) or changes in
family (introducing a separate restricted intranet for the kids) will need a second port.
Also note that there is no longer any cost benefit of buying hubs over network switches, so a switch should be
the only choice because it allows the full 100 Mb to every port, and therefore every machine, on the network. You
should route all network cables back to a single switch located physically next to your Node0 server to minimize
maintenance. In a standard three- or four-bedroom house, this switch should have at least 16 ports.
Server Extensibility
In the corporate world, improving the facilities of a server generally means more memory or more disk space. To us, it
also includes new hardware. Although not all HA applications or servers require new hardware, it is best to consider
what else the server might handle.
TV cards are obvious, because a high-powered server could record from several TV stations at once or transcode
a channel into a head unit-friendly format for streaming. Projects such as PromiseTV ( www.promise.tv ) take this to
an extreme, but it's a viable option.
Similarly, additional sound cards can provide extra scope to functionality. Although the setup in Linux can be
slightly painful, having two sound cards allows you to directly control the audio in other rooms. This can remove the
necessity of having local control panels, since you can use any device that connects to the computer, such as a web
browser, phone, or HR10U connected through Cosmic. Furthermore, remember that each sound card has inputs as
well as outputs. This allows you to build a large-scale baby monitor for each room in the house. If you have a voice
recognition system (covered in Chapter 5), then you have instant control in each room. There have been projects in
the past to coax 6.1-supported sound cards to into three separate stereo ones, but they have not been maintained as
well recently.
Types of Server
Naturally enough, given the title of this topic, the server will be running Linux. It is not by luck that Linux is able to
run on virtually any device, so it's no longer a question of hardware compatibility, but one of compromise between
physical size, power consumption, and CPU power. There is nothing ultimately special about the hardware. Off-the-shelf
machines are fine. You will be familiar with most (if not all) of the devices listed here. We need to consider their
specific relative merits in the HA sphere. In most cases, the server will always have a mouse, keyboard, and monitor
attached (unlike those in the business centers) to allow for simpler software maintenance—and if the server is located
somewhere accessible, the monitor can display a web page presenting the current “house report status” for virtually
zero processing cycles. When these peripherals are not to be connected permanently, you may need to adjust the
BIOS to allow the machine to boot without them. This is especially true of desktop machines that will beep three times
when no monitor is present and often issue the infamous “No keyboard connected - Press F1 to continue” error.