Type of Use as a Requirement for Your Lion Server Hardware

Before you consider the processor speeds for your Mac OS X Lion Server, do some planning to determine what you will be doing with the server. This describes some typical uses listed in approximate order of demand on your server hardware, from least to most demanding.
Web servers: use a lightweight server
Web servers use small amounts of hardware resources. The server often caches web pages and does not need to access the hard drive to load web pages. The web service also does not require a large amount of RAM or processing power. You can run a web server on any Mac that the Lion Server is running on, and you can generally run it with other services without affecting their performance.
Email, DNS (Domain Name Service) and Internet Gateway functionality are similarly lightweight services.
File Servers: Light on the Processor, Big on Storage
File service is not a hardware intensive use of servers. File servers basically need a lot of storage space. You can choose from a wide range of Macs to use as file servers, as long as your Mac has enough hard disk space. Unless you have a lot of users, file servers can run alongside other services.
Backing up Macs and users’ computers to the server with server-based backup software is a kind of file sharing and light use of the server’s processing power.
Database server: transfer a lot of data
If you install a third-party database server, it may take more resources than the file service, especially if a lot of users are accessing the database. A database server can require more frequent use of the hard disk and processor than file servers, depending on the data being served and how often.
Podcast Producer: Processor Intensive Requirements
A podcast product or other video-related server can make heavy use of hardware; It uses a lot of RAM, hard disk space, and processing power to encode the video. Video encoding is also one of the only functions of Mac OS X Server that uses a graphics processor.
Directory Services: Give Her What She Needs
Directory services, which Open Directory provides in Mac OS X Server, can be one of the most used services on a network, especially a large network. Don’t power up the directory server, or you might slow down the entire network.
Directory servers store information about users, groups, permissions, and configuration information for client computers; They authenticate clients and store information that identifies which clients can access files.
Running directory services on a medium-sized network to a large network is equivalent to running multiple databases simultaneously. Fast storage is the most important requirement for directory services for any network of any size. Lots of memory is necessary to maintain performance. For larger networks, consider dedicating a server to directory services. For smaller networks, running the directory service with other services should work fine.

NetBoot: Seriously Durable Server Fatigue
NetBoot probably places more demands on server hardware resources than any other Mac OS X Server service. NetBoot is where client Macs boot from the server itself rather than from their local hard drives. Even for small networks, you need a fast Mac server with multiple processors, fast hard drive storage, and plenty of it.
Wireless networks are too slow for NetBoot, which is why they only support Ethernet connections. A server with multiple Ethernet interfaces can prevent slowdowns. Check Ethernet Adapter: You will need 100BaseT minimum, Gigabit Ethernet will be better. Your network will slow to a crawl if you have an old 10BaseT switch and are using NetBoot.
With so many Mac clients, NetBoot may be too much for a single server to handle, so the software supports load balancing on multiple Mac servers.