Cover the basics to get the most from a multichip server
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If you are plunging toward a server purchase but don't want to waste any of your organization's dollars, keep some basics in mind.
If you are plunging toward a server purchase but don't want to waste any of your organization's dollars, keep some basics in mind.
Processor. A server's processor runs applications and its client-server network operating system. It also controls interactions with other server components such as hard drives and memory.
There are benefits and trade-offs in using a Pentium III or Pentium III Xeon processor. Both Pentium III versions make use of the Dual Independent Bus Architecture, in which one bus is used for the Level 2 cache while the other serves the main memory system. This helps account for the speed and performance boosts offered by the Pentium IIIs.
Memory. Servers use RAM to store software code as the processor reads and executes the code. Dynamic RAM and Synchronous dynamic RAM are the two most common forms of computer memory, with SDRAM offering faster transfer speeds. Obviously, the more memory the better for today's gigabyte-gobbling applications.
Level 2 cache memory is stored on a separate memory chip. Basic Pentium IIIs offer 512K of Level 2 cache; Pentium III Xeon processors offer 1M and 2M of cache memory. greater Level 2 cache memory brings faster speeds to the processing equation.
Error-correcting code is built into the memory systems of most servers so that data is checked for errors and automatically corrected if necessary.
Hard drives. SCSI drives are the most common types used in today's servers. The most popular formats are UltraWide SCSI, running at 40 Mbps, and Ultra2LVD SCSI, running at 80 Mbps.
There could be bays for 10 or more hard drives in a high-performance system. Some are hot-swappable cable drives and can be changed on the fly without shutting down the server. Most of the servers listed offer six or more hot-swap drive bays. Hot-swap SCSI drives usually come in 9G and 18G capacities, with 32G units now entering the market.
Expansion slots. Intel server technology has standardized on the PCI bus architecture, with most systems offering a combination of 32-bit and the newer 64-bit PCI flavors. Many manufacturers still provide a 16-bit ISA slot, or a combination PCI/ISA slot, for hooking up legacy 16-bit appliances.
Mirroring. Some servers offer a reliability feature in the form of data mirroring. When data is recorded to one disk, it is mirrored on a second.
The best mirroring is provided via a hardware controller, but some operating systems, such as Microsoft BackOffice Small Business Server, Microsoft Windows NT Server and Novell NetWare provide software-based mirroring.
RAID. This storage technology is also a cost-effective and efficient way to provide data security, and most server manufacturers offer it as an option. RAID combines two or more hard drives into one logical drive or array so that data may be saved on all of them. Advanced midrange and enterprise servers usually come with hardware RAID controllers.
UPS. Uninterruptible power supplies come as an option with most servers and protect them from power spikes, brownouts and outages that can result in data loss. UPSes compensate for power fluctuations and, in cases of outages, give you time to shut down your servers before they are damaged or lose data.
Tape backup. Most organizations require daily backup of the data stored on a server's hard drives. A tape drive system should contain a larger capacity than the total combined sizes of the hard drives in the server.
Network interface cards. NICs, also known as network adapters, are small circuit boards installed in your servers and client devices. In most cases they provide interconnection to 10-Mbps Ethernet or 100-Mbps Fast Ethernet networks. Consider using a dual-performance 10/100-Mbps Ethernet card for the most flexibility.
Redundancy. Redundant server components provide some guarantee against total system failure in case one or more subsystems fail.
Hot-swap SCSI hard drives can be replaced without powering down the entire system. Hot-plug PCI accessories can likewise be swapped out. Redundant hot-swap NICs make it possible to balance the network traffic load between cards, and if one of them fails another takes over the load. Servers with an optional redundant RAID controller reduce the chances of data loss from a single point of failure.
Configurations. Servers come in rackmount or tower configurations. Towers, or pedestal, designs are independent units; rackmount designs offer a greater amount of flexibility for clustering multiple servers together.
Check out Quantex Microsystems Inc.'s Web site, at www.quantex.com, for the company's summary of server building blocks.
'J.B. Miles
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