SERVING YOU RIGHT

By Ted DrudeSpecial to GCNWith performance and storage demands on systems growing exponentially, managers need to do more than add size and speed to their servers. They need to multiply.For many environments, the new breed of quad-processor servers with Intel Pentium III Xeon chips can provide the answer.Symmetric multiprocessing servers provide scalable performance for midrange and high-end uses. SMP servers split the server workload among multiple CPUs in the same box. This allows sharing of memory, disk storage and network resources for increased efficiency and economy.SMP servers, using dual Pentium II or Pentium III CPUs, are typically adequate for workgroups or entry-level departmental servers.The quad-processor SMP servers, based on Pentium III Xeon processors, are designed to handle much larger workloads.Using multiple high-speed buses for fast data transfer, large memory caches and redundant arrays of independent disks with fast SCSI connections, these modular SMP servers offer a wide range of scalable performance.With the addition of features such as hot-swappable RAID, redundant power supplies and cooling fans, and even hot-swappable PCI slots, these servers are designed to handle mission-critical applications. Last year, Intel Corp. introduced a replacement for the venerable Pentium Pro'the Pentium II Xeon, running at up to 450 MHz. In addition to offering higher clock speeds than the Pentium Pro, the Xeon provides superior performance for SMP servers in at least three ways.First, the Xeon is designed to work in systems with up to eight CPUs, while the Pentium II and III are limited to a maximum of two.Second, the Xeon's internal Level 2 cache is clocked at the same speed as the CPU, rather than the half-speed of the Pentium II and III. This provides an instant 10 percent speed improvement.Third, the Xeon is available with an internal cache size of 512K, 1M or 2M. The latter two versions provide a large boost in performance for server applications that rely heavily on Level 2 cache.As a follow-on to the original Xeon, Intel recently announced the new and improved Pentium III Xeon, which provides even faster clock speeds of up to 550 MHz and a 3-D-augmented instruction set.Most Xeon SMP servers are based on the Intel 450NX chip set, which supports up to four CPUs in a system. These servers typically offer up to 4G of RAM and up to 252G of hot-swappable RAID storage. In a basic configuration, with 128M to 256M of RAM and 9G to 27G of storage, these systems can support large workgroups or departments with up to 100 users.By adding more CPUs, additional RAM and disk storage, the Pentium III Xeon servers can scale up to the size of a high-end departmental server or, when fully loaded, meet the demands of a mid-range enterprise server. This buying guide focuses on quad-processor servers, explaining the options and configurations you should consider when specifying a server from a particular vendor.Xeon servers based on Intel's new Profusion chip set are just now starting to become available. These new servers will offer eight-way processor support, up to 8G of RAM and 1T of disk storage. Combined with a high-end network operating system such as Windows 2000 Server Enterprise Edition, they are designed to provide a level of performance adequate for many large-scale enterprise needs. If even larger computing resources are needed, clusters of Xeon SMP servers can be used, replacing more expensive server solutions.The accompanying chart lists quad-processor Pentium III Xeon servers. Top-tier PC vendors such as Compaq Computer Corp., Dell Computer Corp., Gateway Inc., Hewlett-Packard Co. and IBM Corp. provide highly competitive offerings.Minicomputer and mainframe manufacturers, including Data General Corp., Hitachi Data Systems Corp. and Unisys Corp., also make Xeon servers. And many high-volume PC makers also offer Xeon servers based on a general Intel specification. DTK Computer Inc., Micron Electronics Inc. and Quantex Microsystems Inc. are typically thought of as desktop PC vendors, but they also have credible server options. A newer player in the Intel market, SGI, also recently announced two Xeon server models.On the surface, there is an amazing amount of similarity in all these systems. But many differences can be found in such features as the amount of internal disk storage they support, their advanced performance features'such as 64-bit PCI slots'and various form factor options such as whether they have a tower or a rackmount design.There is also a wide variation among vendors in support of multiple operating systems'Microsoft Windows NT, Unix, Novell NetWare and Linux'bundled server management software and various clustering options. Choose your features wisely, especially when a large number of servers will be installed and managed together.The systems listed include a single 500-MHz or 550-MHz Pentium III Xeon CPU, 128M to 256M of error-correcting code RAM, a minimum 9G hard drive and a 10/100Base-T Ethernet network interface card. The prices run from $5,000 to almost $9,000, but the standard equipment varies considerably.Server options can easily add thousands of dollars to a system's price. Depending on the number of CPUs and the amount of RAM and disk storage you add, along with high-reliability features such as redundant power supplies, the price of the base machine can double easily.A critical option is whether to go with a CPU that has a 512K internal cache, which is standard on most systems, or upgrade to a more expensive CPU with a 1M or 2M cache. Moving to the larger cache will increase the cost by about $1,000 per megabyte per CPU. If you want to add processors later, the cache sizes must match as well.The reason you might want to consider a large-cache CPU is because SMP systems generate a tremendous amount of CPU-to-memory traffic. As more CPUs share the same memory, a larger cache provides a buffer to prevent system bottlenecks as processing loads increase. This makes a big difference in performance, as successful memory hits increase proportionately with larger cache sizes.Memory options are nearly identical in 450NX systems. Most come with a minimum 256M and a maximum 4G of RAM, the current limit supported by Windows NT Server 4.0. Servers based on the Profusion chip set will support up to 8G of RAM.Sizing the core memory on the server will be dictated by the server load and the applications you intend to run. More RAM typically pays off in better performance, unless you are seeing the kind of memory-bus contention described above. Then, only a larger CPU cache will ease the burden.All the servers listed offer built-in SCSI controllers, based on the time-proven Ultra Wide SCSI (UW-SCSI) or the newer Ultra2 SCSI Low Voltage Differential interface. Ultra Wide SCSI offers a maximum data transfer rate of 40 Mbps. Ultra2 SCSI LVD runs at up to 80 Mbps, allows longer cables and more drives to be connected to a single controller, and has less SCSI bus noise than UW-SCSI. Most servers offer two high-speed SCSI channels for the main storage array and a third, narrow SCSI channel for CD-ROM drives and tape backup devices.Server drives are typically available in two flavors: fixed and hot-swappable. The interface type, rotation speed and internal buffer size are all factors that directly affect disk performance. Older, less expensive drives spin at 5,400 rpm. Most newer UW-SCSI or Ultra2 SCSI LVD drives run at 7,200 rpm or 10,000 rpm. A fixed boot drive is often used, in an internal drive bay, with critical data storage saved on a RAID device.Hot-swappable SCSI drives usually are available in 9G or 18G capacity, although 32G models are coming soon.Multiplying the number of available drive bays by the capacity of the drives used tells you the storage capacity of the server. Most models offer six or seven hot-swappable bays.Additional storage usually can be added through external drive enclosures, but that can elevate price considerably.If you know you need maximum storage immediately, you might want to look at servers with more internal bays, such as models from HP, NCR Corp. of Dayton, Ohio, and Unisys that have 11 or 12 hot-swappable bays.Windows NT, Unix and Linux all support software-based Level 5 RAID redundancy, but you need at least three drives of identical size, which typically will mean three 9G drives, for 27G minimum.If you want better performance, a hardware RAID controller is required . It works with the operating system to manage the low-level drive handling and still outperforms software-only solutions by a wide margin. Some servers offer hardware RAID controllers as standard equipment, but usually it's an extra-cost option, unless you are ordering multiple drives with the base system.Most users will run one of four operating systems on an SMP server: Windows NT Server, NetWare, Unix or Linux. Some vendors support all of these OS choices, but the only one common to all the vendors surveyed is Windows NT Server. If you want to run another OS, make sure the hardware of the vendor you choose supports it. Getting necessary device drivers, including RAID software, can often be a trial if you are going it alone.For those who are interested in Linux, the good news is that an increasing number of vendors are supporting it as a second platform after NT. It offers many of the same advantages as Unix, with the benefit of open source code and a wide range of third-party software options. The list of vendors supporting Linux along with NT now includes Compaq, Dell, HP, IBM and SGI. If you are considering a switch to Linux down the road, make sure the vendor you choose can support the move.If you need a server with more horsepower than a dual Pentium III offers, the Pentium III Xeon provides strong and highly reliable performance. For those who need a server that can replace an aging minicomputer or mainframe, the quad-processor SMP servers are an affordable alternative.As eight-way Xeon systems become available, you can expect them to reach even further into the territory once held by big iron. With the ability to serve many hundreds of clients simultaneously and a wide range of scalable horsepower, SMP servers offer a new level of performance for price in the server arena.XXXSPLITXXX-