Hardware Selection Guides and Articles

Processor Selection (Quad Cores, Dual Cores, ...)

"Dual processor" system vs. "dual core" systems?

In any contemporary processor / architecture environment any "dual processor" better well be integrated with [dual] dual core or [dual] quad core processors. The term "dual processor" means that two processors -- also known as central processing units or "CPUs" -- will be used in a given computer architecture, e.g., a "dual processor" workstation or a "dual processor" server. The processors are mounted in packaging which allow them to be mounted in "sockets" on the "motherboard" or main system board. The term dual processor implies processors are separated by an interconnecting bus on the order of several inches at a very minimum and, as a result, data flow delays are quite significant at gigahertz processing speeds. The most recent advancement in small system computing includes dual core and quad core processors and are becoming commonplace on entry level computers. This means two or even four separate processors are built into the same package and the package occupies a single socket. But because the separation between processors within the package is reduced to micrometers rather than millimeters, the dual core processor can process instructions at a much faster rate and is not subject to nearly as much propogation delay. Even the lowest end servers are now configurable with two quad core processors in a dual socket arrangement.Now, why does that matter? Because multithreaded applications such as "Microsoft Exchange Server" can run on one or more processors while another processor is free to handle the operating system overhead  and another doing file serving. The more multithreaded applications your business uses, the more valuable the multicore processor is to efficient computing. The rule of thumb for any class of microprocessors is that for every core added there is a an additive 0.9x multipler to processing speed.  So a dual core is 1.8x faster than a single core and a quad core is 3.6x faster than a single core. Legacy dual processor systems using single cores are typically four to ten times slower in benchmark performance.

In summary, it is generally a far better design to incorporate one dual core processor, than two single core processors of the same class. A great resource for determining speed benchmarks for combinations of dual core, quad core, dual processor and quad processor systems can be found at the PassMark® Software speed test area. From experience, just because a processor costs more when you are making your selection on a custom build does not mean the extra cost is proportional to extra performance and can, in fact, be quite the opposite in benchmark testing. Performance benchmarks for higher end CPUs for use in servers and high end workstations can be found at  http://www.cpubenchmark.net/high_end_cpus.html 

RAID Arrays Explained

Virtual Private Networks

Virtual Private Networks (VPN) allow businesses of all sizes to create a "virtual" network that can connect all of their computers, servers, and Internet Protocol (IP) devices regardless of where the sites are located -- be it San Francisco, San Diego, or San Salvador. Once the security policy is defined for the business, secure interconnection of all IP devices is performed by hardware or software encryption of the data that is transferred between sites or individual computers on the network. The only significant limiting factor becomes the bandwidth of the internet connection type -- whether DSL, Cable, or Optical connectivity -- between sites.

A VPN can:

• Extend geographic connectivity
• Improve security
• Reduce initial and recurring costs over maintaining a dedicated Wide Area Network
• Reduce transit time and transportation costs for remote users
• Improve productivity by simplifying the data storage, transfer, and backup processes
• Provide global networking opportunities
• Provide remote and telecommuter access to data

The following graphic illustrates a VPN connection between corporate offices, remote users, the database and application server and strategic partners. (Courtesy of Cisco Systems)

IPsec is an acronym for Internet Protocol Security Protocol.  IPSec has two encryption modes: tunnel and transport. Tunnel encrypts the header and the packet while transport only encrypts the packet .

Analogies:

Tunnel: The BART tube in the SF Bay Area is analogous to the service provider that moves the headers and packets that have both been encrypted. From the surface nothing can be seen but the data is moving around. No one knows who the data is moving back and forth between.

Transport: A UPS® truck is in charge of carrying packages based on an address on surface streets. UPS knows the address but not the contents. Only the header is free for all to read. The packet is fully encrypted or scrambled data. Anyone who looks at the data packet sees nothing but packing foam. The contents are unknown.

Only systems that are IPSec compliant can take advantage of this protocol. Also, all devices must use a common key and the firewalls of each network must have very similar security policies set up. IPSec can encrypt data between various devices, such as:

• Router to router
• Firewall to router
• PC to server
• PC to router

 VPN Routers manage the encryption automatically, freeing the server for other duties. Remote users will need compatible VPN firewall software installed on their computers to communicate.

Do We Really Need a Server?

While any small business can operate without a server, adding a server, be it in house or virtual, has added benefits which may be useful in justifying the additional costs. If you have two or more computers in any size business, a client-server network configuration can often be justified as opposed to using standalone computers for your information management. The server enables centralized data management and automatic backup. It allows you to even host your own website if you choose. There are very reasonably priced entry level servers that enable even the smallest of business to be more productive, to store data securely, and that can ensure quick recovery in the event of a catastrophic failure, theft, or power loss. The larger question becomes "Can your business afford to not have a server?"

No handling CDs, zip drives, emailing info from user to user, or having to manually backup every PC in the office. Redundant hardware increase the probability of extremely high reliability for the server with only minor increases in cost. Each employer can get seamless access to the data wherever you log on, virtually from anywhere in the world that has internet access. Your computer crashes? Log onto another and you are back in business. It is that simple. Adding an IPsec compliant virtual private network will ensure that that data transfer is encrypted and your information remains private between sites or remote users.

However, more often than not a small business and even some medium sized businesses will not have the resources or perhaps not have the expertise to hire their own IT staff. Perhaps they wish to outsource, even if they do have people capable of managing the IT forest. But even the most honest vendor can ask questions that no one in your office can answer, e.g., What type of server software do you need? Do you want SCSI? How much RAM do you need?, Single Ranked or Dual Ranked RAM?, What Level RAID do you need? How much disk space do you need? Are you going to do remote maintenance? Tape or Disk for Backup?

Until the definition of the needs of the business are extracted through the interview process, it is impossible to know what is the minimum configuration. That leaves the vendor forced to build in lots of margin for error and perhaps much more system than you really need -- just to make sure you do not outgrow your server. But our rule of thumb is to ensure that the server meets the needs of the business or is economically scaleable to meet the needs of a business for at least a five year period. For a fully redundant server this is quite reasonable to expect.

• How many users do you anticipate needing access over the next five years? 
• What business applications do you need served?
• Do you need e-mail served, as well.
• Do you anticipate having a need for a second server in the same domain?
• Do you need to have the local drives on the computers being served backed up?
• Do you want to host a website on the server?

Microsoft Small Business Server bundles Microsoft Exchange, share point services, the O/S and most everything you need to run a small business. But the more features you add, the greater the chance you will have to buy individual software packages at a greatly increased per seat expense. Alternatively Microsoft Server Standard or Enterprise may have more per seat expense, but are scalable to a multiple server environment.

So lets say SBS does fit your needs. Then we can move onto hardware.

Dual and Quad core processors enable multithreaded software applications to run on seperate processors. While faster may be better, sometimes it is wasted, e.g., if your VPN or network connection are bottlenecks.

SBS supports a maximum of 4GB of RAM so any extra is a waste.

SCSI hard disks are very fast, reliable, but quite expensive due to their much more complex design. SAS drives are a serial rather than parallel form of SCSI but still expensive, SATA drives are not as reliable but inexpensive. But properly designed redundant arrays (RAID) can in many cases use these drives with minimal risk to uptime.

Tape Backup is on the way out. Microsoft is dropping support in some of the server packages starting in 2008. Better and faster technolgies are becoming economical to nearly every size server from built-in removalble hard drives to USB mounted SAN storage.

Power supply failures are common. Redundant power supplies ensure a power supply failure does not shut down the server.

Remote management tools allow remote maintenance and even cold boot capability

But of course, all of this adds to the expense. Balancing the cost vs. performance equation can only be made once the medium and long term goals of the business are defined.