Take Control of OS X Server

Take Control of OS X Server


239 Pages


Learn to run your own server for file, calendar, backup, and other services!

Updated February 18, 2016

We won't beat around the bush -- running Apple's OS X Server requires a lot more knowledge and effort than most other activities on the Mac. No matter how easy Apple makes working within the Server app, there are terms, concepts, and procedures you should understand before tackling server installation and management. Unless you know what to enter and why, your server won't work, or worse, its important data will be vulnerable to outside attack or hardware failure.

For anyone in a home or small office situation who needs help with OS X Server, Charles Edge draws on years of experience as the CTO of a national consultancy and managed services provider to give you the essential background explanations, step-by-step instructions, and real-world advice you need to set up and run OS X Server successfully. You'll learn how to set up file sharing, create shared calendars, run your own Web server and wiki, coordinate Mac and iOS software updates for your users, manage your organization's iOS devices (MDM), and provide networked Time Machine backups, among much else. A final chapter offers advice on how to keep your server running smoothly.

Older versions? This book describes 10.11 El Capitan and OS X Server 5. Readers who have OS X Server 3, known as Mavericks Server, should download the 1.0 version of this book. And those who have OS X Server 4, also known as Yosemite Server, can download the 1.1 version. To download these older books, once you've bought this title, click Ebook Extras (page 3 of the PDF) and look in the blog.

You'll find answers to many OS X Server-related questions, including:

  • What's the best Mac to use as a server?
  • How much RAM and drive space should my server have?
  • What's the best way to speed up a server whose performance is lagging?
  • Why is it important to set up directory services early on?
  • Which ports need to be opened to make services available to the Internet?
  • What's the big deal about running a mail server?
  • Is there a good way to share contacts between people? (No, sorry.)
  • Can OS X Server provide a private messaging service?
  • Will I be able to enforce iPad device restrictions via Profile Manager?
  • Does setting up an organization wiki requires the Websites service?
  • Should I use the Software Update or Caching service, or both?
  • What should I do if Time Machine on a client Mac can't connect to the server?

Note: This book assumes that the average reader has one router, one network, and one server (although there are a few spots where it discusses how multiple servers interact). Large installations will have different configurations by necessity. Similarly, the book does not cover imaging, Xsan, or VPNs.



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OS X Server 5!Table of Contents
Read Me First .................................................................3

Introduction ..................................................................5

OS X Serv er Quick Start ..................................................8

What’s New in Server 5 .................................................10

Upgrade to Server 5 ......................................................11

Choosing Server Hardware .............................................15

Preparation and Installation ...........................................24

Directory Services ........................................................52

DNS Service ................................................................74

File Sharing .................................................................82

Collaboration Services ...................................................97

Mail Services ..............................................................121

Mobile Device Management ..........................................141

Web Services .............................................................159

Wiki Services 178

Software Updates .......................................................197

Backup ......................................................................210

Server Maintenance ....................................................219

About This Book .........................................................235

Copyright and Fine Print ..............................................239

2 Read Me First
Welcome to Take Control of OS X Server, version 1. 2, published in
February 2016 by TidBITS Publishing Inc. This book was written by
Charles Edge and edited by Adam Engst, Tonya Engst, and Caroline
This book explains how those in home or small office environments
can set up Apple’s OS X Server to provide file sharing, shared calen -
dars, a group wiki, cached software updates, and a Time Machine–
compatible backup destination, among much else. This book focuses
on OS X 10.11 El Capitan and OS X Server 5, but readers can download
a prior version to find coverage of Server 4 in 10. 10 Yosemite or Server
3 in 10. 9 Mavericks.
Copyright © 2016, Charles Edge. All rights reserved.
Updates and Mo re

You can access extras related to this ebook on the Web (use the link
in Ebook Extras, near the end; it’s available only to purchasers). On
the ebook’s Take Control Extras page, you can:
• Download any available new version of the ebook for free, or buy
any subsequent edition at a discount.
• Download various formats, including PDF, EPUB, and Mobipocket.
(Learn about reading on mobile devices on our Device Advice page.)
• Read the ebook’s blog. You may find new tips or information, as
well as a link to an author interview.
If you bought this ebook from the Take Control Web site, it has been
added to your account, where you can download it in other formats
and access any future updates. However, if you bought this ebook
elsewhere, you can add it to your account manually; see Ebook Extras.
3 Basics

If you need basic directions in order to understand what I mean when
I talk about working with menus, paths, or any other Mac 101–type
topic, please see Read Me First: A Take Control Crash Course,
available for free on the Web or as a standalone ebook in PDF, EPUB, and
the Kindle’s Mobipocket format.
What’s New in Versio n 1.2

This is the third version of this book, with the 1.0 version looking at
Server 3 in 10. 9 Mavericks and the 1.1 update focusing on Server 4 in
10.10 Yosemite. This new version, 1. 2, continues the trend, covering
Server 5 in 10. 11 El Capitan. Despite the change in operating system
requirements, differences in the visual interface, and a variety of small
functional tweaks, the basic features of Server have changed little.
Note: For help with Server 3 or Server 4, you can download a
previous version of this book. See Ebook Extras and click the Blog link.
Here’s a list of the most notable changes:
• Updated screenshots to reflect Server 5’s visual changes
• Updated text to reflect Apple’s new terms and names in Server 5
• Updated the former “What’s New in Yosemite Server” chapter to
describe What’s New in Server 5 . This chapter has handy links to
make it easy to find Server 5–related content in this book.
• Revised the former “Upgrade from Mavericks Server” chapter to
discuss how to Upgrade to Server 5 from Server 4 .
• Updated paths to files that changed between Server 4 and Server 5
due to System Integrity Protection (SIP), Apple’s new way of pro -
tecting the operating system from tampering
4 Introduction
Do you want to provide file, Web, networking, and other services
to the computers on a local area network, including Macs and iOS
devices, and for some services even Windows-based PCs and Android
devices? Or, perhaps you want to distribute content to other computers
on the Internet? Or manage iOS devices and OS X computers from a
central location, caching updates to a single computer for distribution
to iOS and OS X alike? Whether you’re a normal Mac user or an
experienced server administrator, you can do all this with a standard
installation of OS X and the Server app, available from the Mac App
Store—oh, and a little elbow grease!
Long gone are the days when the 10.6 Snow L eopard version of OS X
Server cost $499 and required a completely different operating system
installation. Now OS X Server is encompassed in an app called Server.
It is available from the App Store for $19. 99 and installs on top of a
stock version of 10. 11 El Capitan.
In 2005 when I wrote my first book about Apple servers, they were
usually big, expensive beasts running on Apple’s Xserve hardware and
they required a dedicated operating system (which ran about $500 on
its own). Apple later retired the Xserve, and now the typical machine
you find running OS X Server is a Mac mini. But there’s no require -
ment that you use a Mac mini or any other particular Mac model. Over
the past couple of years, I’ve installed the Server app on everything
from an old MacBook Air to a shiny new Mac Pro. You can make any
Mac running 10. 11 El Capitan into a server, using the steps in this
Back in the Xserve days, Apple tried to make OS X Server do a lot.
The various Server applications could manage podcasting, streaming
media, grid computing, and other services that have since been retired.
No outsider knows why Apple removed these services. Perhaps a
service wasn’t being used enough to justify development, or perhaps
it didn’t fit into Apple’s overall plans (those services started to drop
5 like flies the day the iPad was released). OS X Server is still a great
solution, provided you use it for what Apple intends (although some of
my favorite work has been deploying OS X Server for customers doing
crazy things Apple never imagined or even wants you to do).
An advantage of Apple’s dropping some of the less used services is
that OS X Server has become easier to use, which, combined with the
massive price reduction and the simplified app installation, makes
OS X Server more accessible to the masses than any other server
operating system. The adoption rate is up, and more people are taking
advantage of what OS X Server can do.
That’s all good, but just because OS X Server is easier to use than ever
before, that doesn’t mean it’s something anyone can set up, at least not
without help! No matter how easy Apple makes the Server app, Macs
running it are still servers, so there are terms, concepts, and proce -
dures that you should understand before you take on server installa -
tion and management tasks. L ook at it this way: the Server app may
provide a friendly interface to configuring various services, but unless
you know what to enter and why, things won’t work.
This book is for new administrators of OS X Server and for those who
want to refresh their Server know-how. Perhaps you’re entirely new
to OS X Server but want a centralized file server for your ripped DV Ds
and so that you can manage your kids’ iPads. Or perhaps you’ve
managed OS X Server in the past but are looking to catch up on what’s
possible in the current version.
To provide some boundaries, for this book I’m assuming that the
average reader has one router (such as an AirPort base station running
DHCP and NAT), one network, and one server. In other words, if
you’re setting up multiple servers running OS X Server on a campus-
wide network where every machine is directly accessible from the
Internet, you’ll find good information here, but your configuration will
be different by necessity.
6 Note: Similarly, I don’t cover imaging and Xsan. Both services—
which are really ecosystems on their own, not just services—should
have entire books of their own, as their management is complicated
and should not be taken on lightly. They’re outside the scope of what
I am trying to do with this book, which is provide a good baseline for
getting a server up and running.
Whether you’re an individual user at home or the administrator of
dozens of computers in a busy office, and whether you’re a relative
beginner or a professional system administrator, you’ve come to the
right place to start using OS X Server!
Using Terminal with OS X Server
Although the vast majority of the work you’ll do in setting up and
managing OS X Server happens in the Server app, that app can’t
handle everything you might want to do. As a result, we’ll use
Terminal now and then in this book to work at the command line. I’ll
guide you through the commands to use, all of which will be clearly
formatted so you can follow along easily.
Over the many years I’ve been installing and managing OS X Server,
I’ve learned that having a general comfort level with the command
line is helpful. No matter how simple Apple makes Server, every now
and then I need to go to the command line. But don’t worry, working
at the command line isn’t all that complicated.
And, if you need help with the basics of working at the command line,
read Take Control of the Command Line with Terminal, by Joe Kissell.
7 OS X Server Quick Start
I strongly encourage anyone who is starting from scratch to read
Choosing Server Hardware , Preparation and Installation , and
Directory Services . Or, if you’re upgrading from Server 4 in 10. 10
Yosemite, start with What’s New in Server 5 and Upgrade to Server 5 .
After that, you can read each chapter independently, focusing on
the services you want to run. For example, if your goal is to run a file
server for a small business, you can go through the basics and then
jump to the chapters on File Sharing and Backup, along with the final
chapter, Server Maintenance .
Get started with OS X Server:
• Decide which Mac you want to install OS X Server on, and get
advice about CPU, RAM, disk space, and bandwidth, in Choosing
Server Hardware .
• The most important chapter in the book, Preparation and
Installation, shares key network-related steps you should follow
before installing OS X Server and walks you through the initial
installation and configuration.
• Many services in OS X Server depend on the users and groups you
set up in Apple’s directory service, Open Directory, so it’s important
to set that up early. See Directory Services .
• For improved performance and access to internal servers via name
rather than IP address, you’ll want to go a bit beyond the basics of
OS X Server’s DNS Service.
Set up services for collaboration and communication:
• File Sharing discusses how you can set up a centralized repository
for files and control access to those files.
• The Contacts service enables individual users to share contacts
between their devices, but unfortunately it does not enable contact
sharing between people. See Use the Contacts Service .
8 • With the Calendar service, users can share calendars with one
another without relying on iCloud or another public service. Read
Use the Calendar Service .
• For organizations interested in privacy, the Messages service
enables users to exchange instant messages within the local
network, without using a public network. See Configure the
Messages Service .
• Mail Services looks at the simple task of configuring a mail server
and the far more complex task of preparing to host a mail server.
I recommend against this route, as you’ll read.
• Web Services explains how to set up a Web server running the
industry-standard Apache software.
• In Wiki Services, you’ll learn how to set up and run wikis and blogs
on your server.
Manage devices on your network:
• Mobile Device Management looks at Profile Manager, a tool that
enables you to control apps and settings and set up restrictions on
Macs and iOS devices. Profile Manager also lets you lock and wipe
those devices.
• To save bandwidth and control which Apple and App Store updates
your users see, you’ll want to Configure the Caching Service and
Configure the Software Update Service.
• To set up your server as a destination for Time Machine backups
for users on your network (just like backing up to a Time Capsule),
you’ll want to Enable Time Machine Backups.
Manage your server:
• Make a plan for how you’ll Back Up the Server—and carry it out.
This is key for ensuring that all your work in setting everything up
isn’t lost when a drive goes south!
• Once your server is running smoothly, read Server Maintenance for
maintenance tips on how to keep it that way, plus a smidgen of
problem-solving advice.
9 What’s New in Server 5
Despite the major version number change, which has the community
calling it Server 5 instead of El Capitan Server, OS X Server 5 hasn’t
changed much from Server 4. The changes in Server 5 that readers of
this book are likely to care about include:
• The File Sharing service now has an iOS option. I’ve made several
changes in the File Sharing chapter to mention this new checkbox;
in particular, see the sidebar File Sharing Protocols .
• Fields in the Users panel were shuffled around; see Add a User.
• The Caching service now supports caching iCloud assets, as noted
in About the Caching Service .
• Profile Manager supports new features in iOS 9 and El Capitan,
including pushing OS X enterprise apps and iOS media assets to
devices; see Mobile Device Management.
• Although most readers of this book won’t notice, numerous under -
the-hood changes in Server 5 were required by El Capitan’s addition
of System Integrity Protection (SIP), Apple’s new way of protecting
the operating system from tampering.
If this list seems anemic, note that there are additional changes in
Xsan 4 and Xcode Server, but those are outside the scope of this book.
10 Upgrade to Server 5
Now that you know what has changed, you have to ask yourself, “Do I
need to upgrade now?” There’s no shame in leaving a working server
alone, even if it’s not running the latest and greatest, so if you don’t
need any of the new features and you’re not running into any bugs that
may have been fixed, don’t feel pressured to upgrade. That said, we’re
here to talk about upgrading, not the weather.
Keep in mind that before you upgrade to the new server version, you
should upgrade the operating system from Yosemite to El Capitan, if
you haven’t already. If you need help, read Joe Kissell’s Take Control
of Upgrading to El Capitan. Once that’s done, upgrade OS X Server
itself, again from the Mac App Store.
Note: Technically speaking, OS X Server 5 can run in either Yosemite
or El Capitan, so it’s possible to upgrade to Server 5 without
upgrading to El Capitan; you could just click Update for OS X Server in the
App Store app’s Updates view. However, I don’t recommend that.
El Capitan fixes a number of problems in Yosemite in general, and
I believe that Apple is primarily testing Server 5 in El Capitan, not in
Yosemite. In other words, running Server 5 in Yosemite will probably
work, but for the best results you should upgrade to El Capitan too.
These two installations will likely require about two hours of downtime
on top of the download time for the El Capitan installer. I’ve done the
Server upgrade in an hour or so, but it’s worth making sure everyone
who accesses the server thinks it will take longer, just in case.
Note: I’m assuming that you’re upgrading to Server 5 on the Mac
on which Server 4 currently running. If you’re switching to a different
Mac at the same time, use Migration Assistant to move your
installation. For a more thorough understanding of what is involved, see this
Apple Support article (which currently covers upgrading to Server 4
in Yosemite, but the process is similar for Server 5 in El Capitan).
11 Here are the steps to follow for upgrading:
1. Create a bootable duplicate of your server, making sure to back up
other mounted disks as well, just for safety’s sake.
A good backup provides you with a fallback plan. In the event that
Open Directory, Profile Manager, or other essential services don’t
work after the upgrade, you can always boot from your duplicate
and try the upgrade again later. I like to use a tool such as Carbon
Copy Cloner or SuperDuper to make a bootable duplicate.
2. Download OS X El Capitan from the Mac App Store, and install it
over Yosemite. (Again, if you need help, read Joe Kissell’s Take
Control of Upgrading to El Capitan.)
3. Run through the Setup Assistant after installation.
The IP address host name, and other necessary settings will be
brought over to El Capitan as part of the upgrade process.
Note: If you previously configured the settings in System
Preferences > Network > Advanced to use only Server’s DNS service
(see Update OS X’s DNS Setting), your Mac won’t have Internet
connectivity after you upgrade to El Capitan (since the DNS service
won’t be running). If this bites you, add another DNS server. It can
be either your ISP’s DNS server or a public one like Google’s
4. Install all applicable software updates showing in the App Store
app, and when you’re done, restart the Mac a final time for good
5. Don’t open the Server app yet; first, download OS X Server 5 from
the Mac App Store and install it ( Figure 1 ). It’s a hair over 200 MB
in size.
12 Figure 1: Download and install the Server app from the App Store.
6. Once Server has downloaded, the App Store app notices that you
were running Server before, and tells you that service data has been
preserved (Figure 2 ). Click OK to continue.
Figure 2: The App Store app realizes that you’re upgrading.
7. Open the Server app from the Applications folder, and then click
Continue to update your existing installation ( Figure 3 ).
Figure 3: Click Continue to install Server’s services.
13 8. Agree to the license agreement, and then authenticate using an
administrative account to grant the installer access to otherwise
protected directories on the server.
After a few minutes, provided everything goes well, the Server app
will open.
9. Verify that your hostname and IP address are as they were before
the upgrade, and clear out any alerts about the server’s being
restarted, upgraded, and otherwise tinkered with.
Congratulations! You’ve upgraded to OS X Server 5.
14 Choosing Server Hardware
Perhaps the hardest part of using OS X Server is getting started. What
computer should you use for your server? How much RAM and storage
space should your server have?
As the carpenter’s saying goes, “Measure twice, cut once. ” Rarely is this
truer than when planning to deploy a server. The more people who will
access the shared resources of the server, the more the saying applies.
There are three main areas to consider: Storage, Server Resources
(CPU and RAM) , and Bandwidth. Plus, how you configure your server
depends on what types of services you’ll be hosting, how many of them
you plan to run, and how many users will be connecting. For instance,
file servers typically need more storage and bandwidth. Web and
database CPU and RAM. Servers managing
network services such as Open Directory, DHCP, and DNS are often
not taxed at all in smaller environments, so if you start to tax a server,
it would be better to have redundant servers than to pour additional
resources into a single server.
Note: You can see quick CPU and RAM utilization reports in El Capi-
tan’s Notification Center with widgets such as Bjango’s iStat Mini and
Lukasz Kulas’s Monity.
Note: Software that provides a specific type of content to other
computers is called a service. Each subsequent chapter in the book
focuses on a specific service (or set of related services).
15 Other Hardware Yo u’ll Need
Most Mac servers also have a keyboard, pointing device (trackpad or
mouse), and display, but they don’t need to be new or nice, and they
aren’t technically necessary at all (see the next sidebar).
More important is an uninterruptible power supply (UPS), which
provides battery backup in case of failure. Any machine that
you’re setting up as a server will be running 24/7, and in the event
of a power failure you at least want the option of shutting it down
gracefully if the outage is likely to last longer than the UPS’s battery.
UPSes also condition power, removing spikes and dropouts that can
degrade a computer’s power supply and chips over time. Well-known
UPS manufacturers include APC and Tripp Lite.
How large a UPS you should get depends on the Mac you’re using
and what else you plan to attach to the server, plus any networking
hardware necessary for the server to remain accessible. Both APC
and Tripp Lite offer buying guides to help you choose a UPS.
Running a Headless Server
You can run your server headless, or without a keyboard, pointing
device, and display, but make sure you have these peripherals
handy—for example, shared with another computer you use—in case
your server won’t boot and you need to troubleshoot why.
If you want to keep your server headless most of the time, you’ll
control it via screen sharing, so make sure to enable that in System
Preferences > Sharing before removing the display.
Also, at least some Macs stop using graphics acceleration when no
display is attached, which can result in poor screen rendering
performance even via screen sharing. See this article from Softron Media
Services on how to trick a Mac into thinking a display is connected.
16 Storage

File sizes are growing astronomically. For file servers and backup
servers, you really can’t purchase enough storage, and that’s especially
true if you’re storing video and graphics files. There are two elements
to consider when it comes to storage:
• How much? The total amount of storage should correlate to your
needs, with a bit of future-proofing built in.
• Throughput: Throughput to storage is especially pertinent for
video, database servers, and other data-intensive systems. For most
smaller environments, unless you want to stream video, a Thunder -
bolt or USB 3 storage array is sufficient, with enough space to back
up your data. Throughput to storage can mean that the server boots
faster, as when using SSD as a boot volume or when performing
database lookups; however, for the most part the standard boot
volumes will be fine in smaller environments.
Choosing a Sto rage Vendo r
There are numerous storage vendors, making it hard to know which

ones will provide quality products you can trust. It’s also a
moving market, so any list here would likely be out of date by the

time you read it.

I’m going to go out on a limb and say that you can trust the
equipment Apple sells. There are certainly other great vendors, and if
you know one that you trust or that’s recommended by someone
you trust, by all means purchase from that vendor. Otherwise, check
the Apple online store, since Apple vets the equipment they sell.
When planning storage, consider having a smaller drive or partition
(maybe 100 GB) as the boot volume and a larger one as your data
volume. Separate disks are always fine, but it’s often easier (and a
better use of resources) to make multiple partitions on a disk by
partitioning it in Disk Utility. Also, separating your data and your
operating system keeps the server stable even if you fill up the data
drive and, in the event of corruption or failure, lets you restore one
of them without having to restore both.
17 The only time you want to avoid partitioning is if you’re using SQL
databases or anything else that’s disk-intensive, since performance
will suffer when reads and writes occur to multiple volumes within the
same disk concurrently. In such a situation, each volume should ideally
have either its own dedicated physical drive or dedicated drives in a
RAID configuration.
Don’t Forget Backup Sto rage!
You can never have enough backup storage for a file, database, or
Web server (as I’ll cover in Choose Backup Hardware). The more
backup storage you have, the more versions of old files you can keep
and the less likely you are to have to tweak backups manually once
you’ve completed setting up the server.
Server Reso urces (CPU and RAM)

A stock Mac mini or older Mac Pro usually has ample resources for
offering basic services such as file serving. When figuring out what
Mac to buy or press into service, and how to equip it, you’ll need to
keep two basic variables in mind: CPU power and amount of RAM.
There’s no magic formula for planning a server deployment; however,
the more services you’ll be running, the more memory you’ll need, and
the more users who will access each service, the more CPU you’ll
usually need so that each service can process requests faster.
What about a MacBook o r iMac as a Server?
Although it’s possible to run OS X Server on a MacBook Pro—or

even an 11-inch MacBook Air!—I don’t recommend using a laptop

as a server. They’re not designed to run nonstop, and they’re likely

to have cooling problems.

Conversely, although the iMac works fine as a server, you may not

want to dedicate a Mac with a built-in display to server tasks, since

you likely won’t be looking at its screen much after setup. Opting

for less expensive hardware is fine.

18 Can a Mac Do Double Duty?
Can you run OS X Server on a Mac that you’re using for personal
desktop operations as well? Yes, but I don’t recommend it unless
you’re using OS X Server purely as a personal data syncing solution
to avoid using iCloud for contact and calendar sharing with your own
iOS devices (and even that’s less necessary now—see the TidBITS
article Local Contact/Calendar Syncing Returns in iTunes 11.2).
If other users are accessing services on your personal Mac, they’ll

experience interruptions whenever you restart or let your Mac go to

sleep—and that’s guaranteed to make them cranky. Do yourself a

favor and dedicate a Mac to OS X Server.

How heavily each service will be used determines how powerful a
CPU your server will need. For some environments, such as a home
file server, Apple’s cylindrical Mac Pro would be overkill, unless you’re
also using it for home decor. Stick with a Mac mini for a home file
On the other hand, if you expect to have more than 50 users accessing
your file server, or if your server will be engaged in a CPU-intensive
process like video transcoding, then the top-of-the-line performance
of the Mac Pro may be welcome. And if your budget doesn’t have room
for a new Mac Pro, a previous-generation Mac Pro tower would be a
good compromise.
As I said, the key thing to realize when it comes to RAM is that the
more services you run on a single server, the more memory that server
should have. For example, if a server is going to run directory services,
file services, and shared calendars, plus manage DNS for the network
and manage incoming backups, you’ll need much more memory than
a server that’s hosting only directory services or file services.
Each service requires memory, and I generally recommend at least
4 GB per service. While some services can easily use more than 4 GB
of memory, keep in mind that others can’t use more than 8 GB. You
19 should always start a Mac server with at least 8 GB of memory and go
up from there, depending on how many services you want to run.
When to Add RAM o r Buy a New Server
Let’s say you’ve set up a server using an old Mac mini with 8 GB
of RAM, and performance is lagging. There are two possible causes:
the CPU could be insufficient, or you could need more RAM.
If you can add more RAM, that’s the easiest thing to try. All Mac
minis since the mid-2010 model can take up to 16 GB of RAM, so
max out the RAM and see if your performance problems disappear.
If adding RAM doesn’t help, consider a faster CPU—which in the Mac
world means buying a new machine, since no modern Macs accept
processor upgrades.
There is one other possible solution. If you can’t add enough RAM
to support all the services you want to run, or if you’re concerned
that even a faster CPU won’t solve the problem, it may make sense
to offload some services to another server and run two, rather than
replacing your existing server with a beefier Mac that has a faster
CPU and can accept the necessary amount of RAM.

When it comes to thinking about server performance, you must always
keep bandwidth in mind, but it can be a bit more complex than some of
the other topics in this chapter. At a base level, you must consider the
network interfaces on the clients, the network interface on the server,
and the network link between them.
Since all recent Macs have (or can add via an adapter, in the case of
the MacBook Air) gigabit Ethernet ports, you’ll get the best perfor -
mance if client computers access the server using Ethernet (assuming
your Ethernet cabling is in good shape and you have a gigabit Ethernet
switch) rather than over Wi-Fi connections.
You can run into trouble with Wi-Fi. In theory, 802. 11g maxes out
at 54 megabits per second (Mbps), 802. 11n can hit 150 Mbps, and
802.11ac can go as high as 1.3 gigabits per second. In the real world,
20 though, throughput is dependent on many variables and never reaches
the advertised maximums. In short, Wi-Fi is likely to be a lot slower
than Ethernet.
The practical upshot is that because Ethernet is faster, your server
should be connected to your network solely via Ethernet, and any
client computers for whom performance is important should also
be on Ethernet when possible. Wi-Fi is faster than ever with newer
networks and is usually fine; however, if a computer sits still all day,
it might as well be wired into the network.
Even then, meeting bandwidth requirements is a growing challenge,
thanks to the continual increase in the amount of data being pushed
through servers. If you’re deploying a file server, consider how many
people will be opening and saving files from the server simultaneously,
such as first thing in the morning when everyone comes in or at the
end of the day.
For instance, a small ad production company might have ten people
who have to work on a 5 GB video file; even if the company’s server
is a Mac Pro with gigabit Ethernet, it could take well over a minute
for a user to open the file. That’s an eternity.
When you think about bandwidth requirements, note that the
potential throughput required is the number of users accessing files
multiplied by the size of the typical files accessed. So consider how
a typical user would access files and multiply that person’s maximum
throughput by the number of users, keeping in mind what your
network type can do. For instance, with ten users going over gigabit
Ethernet interfaces, you could have a maximum throughput of
10 gigabits, which a single gigabit Ethernet interface can’t provide.
21 Luckily, there are three main ways of increasing bandwidth, and
while the specifics are beyond the scope of this book, the following
advice should set you on the right path. These options can be pricey
(and are listed here in order of increasing expense), but time is
money, so if you need the speed:
• Provide an interface for each user. Mac Pros have a lot of
Thunderbolt ports, each of which can have a Thunderbolt to
Gigabit Ethernet Adapter with its own IP address, making it
possible for each user to have a dedicated network interface.
• Consider bonding multiple Ethernet ports together using link
aggregation. To use link aggregation, you need a switch that
supports the feature. A beneficial side effect of link aggregation
is redundancy: if one Ethernet port goes down, the overall
connection remains active, with the remaining ports maintaining
• If you’re using a Mac Pro as your server, invest in a 10-gigabit
Ethernet interface. This will require 10-gigabit switches and net -
work adapters, plus at least Cat6 Ethernet cabling. You can even
bond multiple 10-gigabit switches until you get to the point where
you’ve saturated disk access on the server itself.
Realistically, most people reading this book won’t need to go to such
lengths. If the amount of time users will have to wait for files to open
and save is satisfactory to all parties, there’s no need to have more
than the standard gigabit Ethernet interface. And if you’re running an
outwardly facing Web server on a network with a 10 Mbps uplink, you
aren’t likely to ever saturate a gigabit Ethernet interface.
22 When and Where to Buy
Now that you have a sense of what to shop for, where should you
buy it? The Apple Store and Apple resellers can sell you all the
hardware you need. Contact them with a list of your requirements
to place an order.
When a new model of a Mac comes out, there’s often a delay in
getting it. Plus, most servers are built to order, with faster CPUs
and more RAM, so expect to wait 1–3 weeks for components to ship,
according to the supply; for example, fibre channel RAID s usually
take a few weeks to ship. However, a stock Mac mini usually ships
on the day it’s ordered.
Ordering hardware is usually the easiest (and costliest) aspect of
setting up a server. When you place an order, you can ask your sales
professional to give you a sanity check on whether you’re purchasing
the right hardware. Remember, the Server app will be an additional
download (covered in Download and Install the Server App).
Plan fo r Ongo ing Co sts
Don’t forget about annual costs! When budgeting, consider that
you’re likely to replace the server every 3–4 years and that Apple
servers will get free upgrades to OS X every year or so.
Also budget time for care and feeding. I usually like to plan on
someone spending about an hour per month for each service running
on the server. This time is spent troubleshooting, updating, and
managing the server and is an approximate average of what I saw
across the hundreds of servers managed by my previous company.
For more details, see Server Maintenance.