Notice: This material is excerpted from Running A Perfect Internet Site with Linux, ISBN: 0-7897-0514-1. The electronic version of this material has not been through the final proof reading stage that the book goes through before being published in printed form. Some errors may exist here that are corrected before the book is published. This material is provided "as is" without any warranty of any kind.

Copyright ©1996, Que Corporation. All rights reserved. No part of this book may be used or reproduced in any form or by any means, or stored in a database or retrieval system without prior written permission of the publisher except in the case of brief quotations embodied in critical articles and reviews. Making copies of any part of this book for any purpose other than your own personal use is a violation of United States copyright laws. For information, address Que Corporation, 201 West 103rd Street, Indianapolis, IN 46290 or at support@mcp .com.

Chapter 2 - What Kind of Hardware and Connection You'll Need

Equipment and connection types are important, but they become even more important when you set up a site. This is especially true if you make your site an Internet provider, in which case you need to seriously consider what you want to be able to provide with it early; it's much harder to make additions later. Keep in mind that as great as hardware updates are, adding one thing to a system seems to usually cause three other seemingly unrelated things to break. If you're going to provide service to outside users, it's an excellent idea to be as ahead of the game on hardware as possible. Users don't tend to be very patient when systems have to go down for upgrades and for unexpected glitches!

In this chapter, you learn how to:

Choosing Your Hardware

 Choosing hardware is mostly a matter of mixing technical understanding with common sense. The technical side is that each aspect of your computer's hardware affects the speed and efficiency of your services. The common sense side is to get the best hardware you can afford, focusing on which pieces will give you the most bang for your buck when it comes to what services you want to have available.

What hardware you need is subject to many variables. If you determine that what you need is more than you can currently afford to buy, decide what is most important to you in the beginning and where you can skimp for now. Some hardware is more easily upgraded or added to than others, for example.

Because you're focusing on setting up an Internet service, some hardware is more important than others. For example, your main server's graphics capabilities can easily be next to nil. The only machines that will need to be able to display graphics are the ones you want to be able to display graphics (e.g., for Web page development). Other items that aren't necessarily important are:

Consult the Linux Hardware How-To (listed in Appendix F) for brands of hardware that Linux supports. Linux supports a wide range of makes and models, but drivers aren't always available-occasionally new items come out or specs are unobtainable. You can save yourself a lot of hassle by consulting the hardware how-to carefully.

For up-to-date information on the types of hardware available, check out the PC Hardware FAQ by FTP at rtfm.mit.edu, in the directory /pub/usenet/news.answers/pc-hardware-faq. It comes in five parts.

How Your CPU Affects Performance

The speed of your CPU directly affects how quickly your computer can process. Think of the CPU speed as the baseline speed from which all other performance is measured. If you're going to run a site for yourself and one or two other users, and you're going to use your server as your primary console, you can get by with a 486DX33. However, even with a low load, this server may be a little slow (especially if you intend to use XWindows). If you're going to have multiple machines, and you're going to use your server as a server and not as a console, a 486DX33's speed can be sufficient.

If you will have more than around three or four users, you will likely want a faster server (see table 2.1). It becomes especially important as you get more users that your server be used as a server, not as a console, except for server maintenance. However, do keep in mind that important things like program compilation are heavily influenced by CPU speed. A compilation can take over an hour to do on a 486DX33, but only a few minutes on a Pentium. While you compile the program, everything else slows down (mail processing, mail writing, file editing, and whatever other things you may be trying to do).

Using your server as a console on a regular basis means that you're taking up RAM that would normally be used for server functions for your other tasks. You're also using the server's hard drive, CPU, and so on. The combination of these things means slower server response for all the services handled by your main server. Compiling large programs is especially slow unless you severely nice the process (nicing processes are discussed in chapter 5, "Setting Up Your Site for General Use").

There are various types of motherboards on the market:

486DX33 Two users Mailing list 486DX-2 66 Five users Mailing list Small compilation Pentium Ten or more users Three mailing lists Two compilations

The motherboard is the hardest part of your computer to upgrade, and the CPU is built into the motherboard. If you have to get a slower computer than you would like initially, be sure to get one that is easily upgraded to faster speeds.

A motherboard may require two basic types of RAM chips distinguished by the number of pins that connect the chip to the motherboard: 30-pin RAM, and 72-pin RAM. You should get a motherboard that uses 72 pin RAM, which is the newer type of chip and more technologically advanced (e.g., faster memory access).

The type of RAM a motherboard requires goes beyond pins. The time it takes the CPU to access the RAM in nanoseconds (ns) is also important. The higher the ns is, the slower the access. Also, the bus size (expressed in bits) is important, and equivalent to bandwidth. The more bits in the bus, the faster things pass through your RAM. Your motherboard manual will list the other important features your RAM must have, but I've discussed the ones that are important to look at when buying the RAM.

Be sure that your motherboard is easy to upgrade memory-wise. The fewer requirements on what kinds of combinations of chips you have to have, the more flexibility you have in buying RAM.

If you're buying a Pentium machine, pay attention to the bus size and nanoseconds. If you're being offered a "steal" on a Pentium, chances are that you're getting low-quality materials. Be sure to get a quality motherboard.

You can do a good number of things with a slower server, they will simply take longer-sometimes a lot longer.

How Your RAM Affects Performance

The amount of RAM your computer has is a significant factor in how many processes your server can handle at once, and how quickly it can chug through them. RAM can make the difference with things like:

In all the above cases, the more RAM you have, the more items (Web pages, pieces of e-mail, Gopher files) you can load simultaneously. This means that multiple requests are processed faster, because instead of going through one at a time, they're going through 2, 5, or more at a time (see table 2.2). If you have a mailing list of 500 people, this can make quite a difference in how quickly the mail gets sent out.

You should have at least 8M of RAM for a site just for personal use. If you have a few users, and one server handling everything, you will likely want 16M of RAM. If you will have more than 4 or 5 simultaneous users, you may want more than 16M. This is especially true as the numbers get even higher.

How much you need as your number of simultaneous users rises depends often on what the users are doing on your system. Once you get past about 8 simultaneous users, one rule of thumb is 2M of memory for each simultaneous user. I stress simultaneous users because you don't need 200M of RAM if you have 100 users registered on your system. Instead, if you have 28 modems to cover these users, you need 28Ʀ or 56M.

If most of your users don't use applications that take up a lot of memory, you can do with less than 2M per user.Table 2.2 RAM Requirements Relative to Number of Users and Usage Requirements

Users Usage Amount of RAM Two Mailing list 8M Incoming news Five Two mailing lists 16M Incoming news Two Web page requests Ten Three mailing lists 24M Incoming news Six Web page requests Three Gopher requests

You may find that you can live with the results of having less RAM than recommended above. RAM is simple to upgrade when it comes to your system, as long as the RAM works on your motherboard. There's no software reconfiguration required after the upgrade. Therefore, if you would rather skimp on the RAM for now and see how it does, it's not really a problem. If you have a lot of users lined up already, simply be prepared to dash out and buy more RAM as payments come in. See chapter 15, "Upgrading Your System" for considerations on how to handle the upgrade.
If you do have to skimp on RAM, take a look at the discussion of swap space in chapter 3, "Getting Ready To Install Linux from the CD-ROM."

How Your Hard Drive Affects Performance

For a site with one or just a few users, the hard drive isn't the primary consideration when it comes to performance. However, as the number of users and demand on services increases, the size and type of your hard drive becomes more important.

Choosing the Size of Your Hard Drive

The size of hard drive you should choose depends on how much you want to store. You will want a minimum of 200M for a full site Linux installation. Unless you're running a site only for yourself and don't intend to do much, you will want more space than that. With the prices of large hard drives dropping as they are, aim for a minimum of an 850M hard drive.

You can set disk quotas for your users. Often, 10M per user may be a good starting place (I have seen as low as 1M per user). Because there are few people on my system, I don't have quotas set and can get a bit excessive, up to 20M in the home directories. Drive space usage depends on how much mail and news people save, how many personal clients people install, and how many other programs and files folks keep lying around. Using quotas forces people to keep their home directories tidied and not to leave old stuff lying around.

Remember that the 10M per user doesn't cover mail storage, news storage (if you run your own server), POP storage, UUCP storage, and so on. You need to include space for storage of all these items (the ones you're using) in your estimates. Try to anticipate on the high side to save yourself some grief later.

If you're unfamiliar with POP and UUCP, see chapter 6, "Installing E-mail Server Software."

Choosing the Type of Hard Drive

As you get more users, the access speeds for your hard drive, and therefore the drive type, become more important. Even if you don't have a huge number of users, the drive type is important if you have a lot of traffic among services that are drive intensive. These services include:

The hard drives that most people buy with their computers are IDE drives (the standard internal hard drive most people own). These drives are great for most computer users, but they can access only one file at a time. If you'll be running a large site you should seriously consider getting a SCSI drive.

SCSI hard drives can access multiple files concurrently; get one of these drives if you want faster, more efficient file access. A SCSI drive speeds up mail and news processing immensely!

A fast SCSI drive also makes for faster swap space than an IDE drive.

Once your site has hundreds of users, consider buying a Redundant Array of Inexpensive Disks unit (RAID). A RAID unit contains a number of disks all working together in parallel. It acts like one huge drive, but instead stores your site's information on a number of disks instead of just one. When your site has thousands of users, one of these storage units is absolutely necessary.

How Your Monitor and Card Affect Performance

The monitor and video card are only important on machines where you will run XWindows. You will want an SVGA card (if you can afford it, get an accelerated one) and a monitor that works with the card. Be sure to have enough memory on the card to handle the graphics modes you want to be able to use (this information should be available in the card's manual, or from the salesperson). This would be typically 1 to 2M of VRAM (Video RAM).

Of course, if you don't want to run X-Windows (or see graphics) on a particular machine, there's no need to have a high-end graphics setup for it. You only need to consider graphics capability on machines where you want to be able to use graphics.

It is imperative that you check with the Hardware How-To to be sure that Linux XWindows supports your card and monitor.

Dealing with Power Outages

You don't want UNIX systems like Linux to just die with a power outage. Not only will all your users be rather unhappy, but you will lose all the partial files and bits of data sitting around in your system's memory that were supposed to be written to disk. One item you'll want to seriously consider for your site is an Uninterruptable Power Supply (UPS).

Be sure to look in the Hardware How-To to make sure you get a UPS that has a driver available.

UPS's have power ratings on the packaging. Take a look at the power supplies on the backs of your computers, monitors, and any other devices you want to plug into the UPS. Add up the wattage listed on all of these and find a UPS rated for that many watts. If you will have a large number of machines, you may find that it's easier and more economical to buy a number of UPS's. There's nothing wrong with having more than one, and in fact it's a nice redundant safety measure.

The more items you have plugged into a UPS, the faster its battery will drain once power goes out, so it's not a good idea to put important equipment all on one UPS. You may want a single UPS for your main server and its monitor, and another one for peripheral machines.

A great feature to have on a UPS is a network port, which is a serial port going into the back of the device. You connect this to a serial port on one of the machines the UPS is connected to. You can then use the unipower package (the Hardware How-To lists where to get this item by FTP). This package watches the UPS's serial port. If it gets a signal from the UPS, it knows that the power has gone out and it needs to start a shutdown (you set the amount of time before it shuts down). If it gets a second signal before shutdown, the program knows that the power is back or it was just a spike, and cancels the shutdown. This gives your system a chance to save everything from its buffers.

You need a nonstandard serial cable for the network port. Be sure to ask about the cable(s) when you go to buy the UPS(es).

Providing Dial-ins

If you intend to provide dial-ins for your users, you need to also provide modems for them to dial into. What method you use to provide these dial-ins depends on the number of people you want to allow to connect at once.

Small Number of Dial-in Users

If you want to only allow 16 or less dial-ins at one time, you can get multiport serial cards. See the Hardware How-To for what multiport cards have drivers available. Be sure to get the DB25 boards, which have cabling for external modem hookups.

These cards come with various numbers of ports, typically 4, 8, and 16. Remember, you will need an incoming phone line for each dial-in, and a modem to connect the phone line and the card.

How many dial-ins should you start out with? Most service providers try to follow the rule of thumb of 1 modem for every 10 users. Once your system is up and running, have it keep track of dial-ins and use this formula to determine when you need to add more modems:
Chapter 5, "Setting Up Your Site for General Use," has more information.

Large Number of Dial-in Users

If you need more than 16 incoming connections, you should get a terminal server. You might be able to fit extra multiport cards into one machine, but it will be so slowed down by handling all the logins that your server won't be very useful for anything else. If you get a terminal server, it can handle the logins, and your site server can handle everything else.

Use the same formula as listed in the previous section to keep track of how many dial-ins you have.

The key to buying a terminal server is to buy one that has plenty of room to upgrade. Buy one that supports the number of dial-ins you feel you initially need, and with room to expand as far as you think you may need to in the near future. If necessary, you can always buy another terminal server.

For information on the terminal servers available, look in the following places:

Choosing Your Connection Type

The speed, or bandwidth, of your connection makes all the difference in the world when it comes to how quickly your data will travel to and from the Internet. Think of your bandwidth as lanes on a highway. The wider the road, the more data can pass through.

If you think you may want something faster than a SLIP/PPP modem connection, check around with your local service providers and phone company to see what options you have, and what the costs are. Costs and availability of connections vary widely from place to place. There may even be alternative companies that can offer you faster digital connections.

When I discuss numbers of users regarding bandwidth, I'm talking about the number of users who are using the Internet connection at the same time.

The bandwidth you need depends on your site's demands. Let's take a look at the options.

SLIP/PPP Over a Standard Voice Line

If you will have only a few users, a 28.8 kbps permanent connection is sufficient for most occasions. Also, this option is probably the least expensive you will find in your area. Make sure that the number you dial to connect to your provider is not a toll number because you'll use it all the time!

If you want to move up to the next step faster in connections (ISDN, which is discussed in a moment), but it is far too expensive, another alternative may be to use two 28.8 KB modems and two standard phone lines. Using a technique called EQL load balancing, you can then use the two lines together to double your bandwidth (if your service provider supports this). If you consider this option, be sure to check into the cost of upgrading to ISDN and into the cost of permanent connections to the provider. You can then weigh the options and choose the least expensive. See the Net-2 HowTo for more information.

ISDN

ISDN (Integrated Services Digital Network) doesn't use standard modems. Instead, it uses digital modems (or a computer designated to only be your router, turning your data into ISDN protocols). With this type of connection, you get 64 kbps speeds, and it still has a spare channel you can use for voice (and fax, and anything else you'd like to use it for) over the same line! If you don't want to use your ISDN line for voice communications, you can even combine the two primary channels (called bonding) to get 128 kbps! Small providers and businesses often use ISDN connections.

An ISDN line has two types of channels, labeled D and B. The D channel carries 16 kbps and is used for signaling, which means it carries all the control information necessary to handle the connections the data channels use. The B channel (the primary channel I referred to earlier) carries 64 kbps and is used for data transmission.

Often an ISDN connection comes with a D channel plus two B channels, giving you 16 kbps worth of control data transfer speed plus 128 kbps worth of data transfer. However, sometimes the phone company charges extra for the second B channel. This can be for a number of reasons, one being that phone company's lines might need to be upgraded before it can offer that high of a transfer rate to your location.

Unfortunately, ISDN is not available in some areas yet, because while it runs on standard copper phone lines, it doesn't behave like a standard phone line. The phone company has to be set up in your area to support its special behavior before it can offer ISDN. Some of the differences are:

The ISDN I'm discussing here, the one that works over copper wire, is technically Narrowband ISDN. There is another version that works over fiber optics lines, called Broadband ISDN (B-ISDN). Of course, fiber line is much faster for data transfer than copper. At the time this book was written, B-ISDN was still mostly in development stages, but you may want to ask your phone company how close it is to a reality in your area.

You need to buy extra equipment if you use an ISDN connection. You'll need at least one of the following:

Be sure that one of the units you buy to handle your connection also can provide power-a number of them are designed to do so. If they are, you don't have to add extra power outlets to your office. ISDN lines don't contain enough power in themselves to run your phones. If your power goes out, you will also lose phone service and your connection. A UPS may be helpful in giving you some time to shut things down.

Your phone company and service provider should be able to advise you of the best equipment options available at the time you're looking into buying. Shop around as much as you can, as rates can vary widely even within a small area. You may find that you can lease or rent the equipment you need.

You may want to pick up Que's Special Edition Using ISDN if you plan to use an ISDN connection. The WWW also has a great deal of information about ISDN.

When this book was written, Linux drivers for ISDN cards were still in the experimental stage. See the Net-2 How-To for up-to-date information on what's available. You'll need to keep in mind what equipment you can get drivers for when you make your purchases.

T1

T1 lines are even faster digital connections-1.544 mbps divided over 24 channels (which can be subdivided further) traveling along twisted-pair copper wires. These are serious, expensive connections that also require the phone company to lay a line to your location (which means you will need to discuss it with your phone company and find out the costs involved). You will also need to buy or rent special hardware to run and maintain your connection, and find a provider that has the bandwidth to be able to feed your T1 connection to the Internet.

As with ISDN, a T1 is a digital line, with the same types of considerations involved (lack of dial tone, special digital equipment required). Often, you can lease or rent the necessary equipment for your end from your provider and/or phone company (e.g., a router machine to handle your Internet connection, phones, and so on).

With T1, you can use the software in the router to manage where each of the 24 channels goes. You can assign them to voice transmission (phones), video transmission, and so on and even change them dynamically according to your needs. The handy thing about the router is that you don't need special software or drivers on your Linux machines to use the T1 connection. You simply network the router to the rest via Ethernet and the router handles the rest.

Again, as with ISDN, talk to your phone company and your provider for up-to-date information on the hardware and software available. Shop around. Check out the Web-a number of companies are already offering hardware there.

The advantage of buying from your service provider, phone company, or a local computer consultant is that you can probably get your router preconfigured to the necessary settings. Then, you can simply take it, plug it in, and just do a little local setup. If you buy from a remote manufacturer, you may have to go through the headaches of getting all the settings from your phone company, provider, and so on. If you find you'd rather buy from a remote manufacturer, be sure to discuss what you will need to do when the machine arrives so that you're as prepared as possible.

You can get a router machine for ISDN connections as well. You don't need one, however, because of the availability of digital modems. Linux machines can handle routing themselves.

You might not be able to afford a full T1 line for your site, but you may be able to find an affordable FT1 (fractional T1) connection. These lines are generally offered in a multiple of 56 kbps, up to the full T1 bandwidth of 1.54 mbps.

Large corporations, universities, and large service providers generally use T1 lines and FT1 lines.

You can use parallel T1 lines to gain bandwidth. A provider I dealt with recently had around 8000 subscribers, and was using multiple T1 lines.

T3

T3 lines are the cream of the crop, at 45 mbps (equivalent to 28 T1 lines) traveling along special cabling containing fiber optics. T3 connections are rare because of the expense and the special cabling.

An important thing to note about T3 is that no specific standard for all T3 lines exists (as of the time this book was written). You'll need to ask your phone company about the specifics of how its T3 connections are set up. What they all have in common is that they are all high-speed digital lines. Therefore, again, you will need specialized equipment to handle the connection, the phones, and so on. Your phone company and/or provider can be of assistance with either leasing you the equipment, or with pointing you to a good manufacturer.

You can get a partial FT3 connection. In fact, you can get partial FT3 through T1 technology.

Only the largest sites will need and can afford T3 lines. If you find that no combination of T1 lines is enough for your site, it's time to move on to T3.

Cable Companies

Cable companies are slowly maneuvering themselves into the market of service providing. Their coaxial cable can handle up to 10 mbps, which makes it an excellent transmitter for voice, video, Internet data, and so on. At the time this book was written, most cable companies were not yet poised to enter the providing market. There were some interesting experiments going on in various communities, however.

These experiments mostly involve the principle of the Information Superhighway, integrating video-on-demand services, video catalogs to browse, multiplayer games, home shopping, standard cable television, Internet access and more. The techniques and technologies used in the various test runs are different, as well as the services offered.

You may want to check with your cable company and see how far they are from offering such services in your area. The connections they offer are digital, requiring "cable modems" to handle the Internet connection, and special boxes often containing high-powered computer motherboards to handle the video aspects.

Phone Companies

Phone companies are also maneuvering into the Internet service providing business. Some are already there to a limited extent, while others are just entering the market. To find out what your phone company has available, contact its customer service department or if it has one, its technology or networking department.

Often, the networking services offered by the phone company are bundled with digital connections (e.g., ISDN, T1, and so on).

One new item to watch out for is a new method of high-speed communications over standard copper phone lines developed by AT&T Paradyne. It's called GlobeSpan; it's digital; and it gets an amazing 6 mpbs!

Connection Summary

The connection's section contains a lot of important information to digest. In general, the speed of the connection you need is related to the number of simultaneous users you'll have on your site (see table 2.3). These are simultaneous users-users who are all logged in and taxing your connection at the same time.

Your mileage may vary. It's best to simply make sure that you have room to upgrade your connection if you need to.Table 2.3 Which Kind of Connection You'll Need for Number of Users, Considering Usage Time 

Max
Simult.		Connection
Users	Usage	Type	Notes
5	Low	28.8 Modem
3	High	28.8 Modem
20	Low	ISDN, 1B	If available in your area
12	High	ISDN, 1B	If available in your area
40	Low	ISDN, 2B	If available in your area
30	High	ISDN, 2B	If available in your area
100's	Low	T1	If available in your
area, if you run into 1000's of users you will eventually need more than one T1
100	High	T1	If available in your area

By low, I'm referring to that number of users doing things that don't take up a lot of solid Internet connection time. These are things like using the Web (not a lot of graphics or FTP links), Gopher, IRC, and other nonbandwidth-intensive services.
By high, I'm referring to that number of users doing things that take up a lot of bandwidth. These are things such as using the Web and accessing a lot of Web graphics or FTP links.

Choosing Your Provider

It's important to shop around when you're looking for a provider to carry your site to the Internet. Your location will determine how many providers you have to choose from, and what services they can offer you.

Some things to consider in choosing your provider are:

  1. Expandability. How much do you think you will expand with time? Are you starting with a 28.8 SLIP connection and think one day you may need an ISDN or T1? Try to pick a provider that can support at least one step of growth. You don't want to have to tell InterNIC that you've moved too often because of the time it can take to get all your routing straightened out. You could end up in limbo if the Internet thinks it's supposed to send your packets to one location, but you're at another.
  2. Affordability. Prices for services can vary widely. One local provider quoted me a setup fee of over two thousand dollars for a standard 28.8 SLIP permanent connection, while another provider waived the fee because it was a simple setup, and I could handle most of the setup on my own. Try to realistically assess how much assistance you want when discussing setup fees. I had set up such a connection before, so, for me, doing it myself wasn't a big deal. Setting up a much more complex connection where I'm unfamiliar with the technology involved might be something I don't have the time to fool with until I get it right. Sometimes, it's worth paying a setup fee to have the extra technical support. Some providers won't waive the setup fee because they assume that you will need their technical help at some point.
  3. Reliability. Ask around, find out what other people in your area have to say about the available providers. Keep in mind that you will not be going through the provider's normal system. Basically, with a permanent connection (even a modem one at 28.8) you're connecting to a machine that goes straight to the Internet instead of going through the provider's internal network. Therefore, you probably want to try to find someone who has a permanent connection of the same type you want with the provider you're checking out (e.g., if you want an ISDN 2B connection, see if you can find someone else who has one, and ask him how reliable it is and about the technical support and customer service).
  4. When it comes to permanent connections, providers will sometimes offer references in the form of other customers. You can also check on local newsgroups through another Internet account.

If you're eager to get to the installation, you can get your server machine and install Linux there now. You don't need to be connected to your provider to set up the basic system or the servers themselves, but you won't be able to test the servers until you've got your system connected to your provider. Also, you don't need any other machines for your site until you have the server set up, because it's the machine that will run your entire network. Once you set up the server, you can install Linux on the other machines.
If you don't want to set up any extra machines until the server is fully functional, you can install client programs on the server to test it. However, if you don't want to bog down the server with such items, you may want to set up one additional machine, network it to the server, and test your clients on that machine. You should do this especially if you want to be able to test Web items with graphics, and don't intend to get a server that can handle graphics display.

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