Powerhouse Pentium Pro Servers

With Intel's latest 200-MHz CPU, cost-effective quad-Pentium Pro servers reach new performance levels.

Dave Rowell and Peter D. Varhol

When Intel designed the Pentium Pro processor, it had more than just the desktop market in mind. With internal parity-checked registers, ECC-protected (error-correction code) caches, built-in diagnostics, and the ability to maintain L2 cache coherency with up to four processors, the Pentium Pro should make one heck of a server. Coupling the Pentium Pro with its 82450GX PCI chip set, Intel provided high-end PC vendors with a compelling server architecture that adapts to the needs of customers entering the midrange server market.

It's taken almost a year to get the bugs out of Intel's complex chip set (or work around them), but the first quad-Pentium Pro servers are proving both capable and cost-effective. We got our hands on two of the first systems to use Intel's latest 512-KB-cache version of the 200-MHz Pentium Pro and find that they make impressive application servers. We looked at preproduction versions of ALR's Revolution Qu ad6 and Compaq's ProLiant 5000 in July, both equipped with four 200-MHz/512-KB Pentium Pros. Similar systems should now be available from Dell, Digital Equipment, Hewlett-Packard, IBM, Intergraph, and IPC.

Clearly, the Intel architecture coupled with industry-standard peripherals can offer much lower costs than an architecture and peripherals designed for one of the lower-volume RISC processors. The systems evaluated here have starting prices between $30,000 and $35,000 for four-processor configurations. Up against midrange servers from the likes of Sun Microsystems and HP, this represents a potentially attractive price.

What's There to RISC?

Price has never been the biggest factor in buying a server, however. Performance -- especially reliability -- comes first. The 200-MHz Pentium Pro has integer performance highly competitive with RISC chips, and coupled with competent memory, I/O, and mass-storage subsystems, it does well as a database server.

Testing with the industry-standard TPC-C database-server benchmark, Compaq has reported results from a 166-MHz quad-Pentium Pro ProLiant system of 5676 transactions per minute (tpmC) running Windows NT 4.0 and SQL Server 6.5 at $136 per tpmC, which is comparable to many low-end and midrange RISC servers. (That system had 2 GB of RAM and 391 GB of hard drive storage.) Testing a similar 166-MHz setup with a Sybase/UnixWare combination, Compaq reports 6186 tpmC.

To operate as servers, these systems must have high availability, something the traditional PC architecture has not been well known for. Intel's architecture provides for some redundancy, such as the ability to run on any number of avai lable processors, but leaves it up to system vendors to complete the picture.

While neither vendor offers a totally redundant design, both ALR and Compaq implement reliability features formerly found only on more expensive systems ( see the features table ) and offer options like redundant power supplies. ALR's power-supply option has load sharing and separate power cords so you can power them from different sources; Compaq's has a single power cord.

Both vendors offer high-performance, hot-pluggable RAID options. They provide the systems with built-in sensors to monitor operating temperatures and catch failure of critical components (e.g., fans and power supplies). Compaq's Insight Manager and ALR's InforManager software provide extensive and sophisticated abilities to notify system administrators of problems.

Compaq takes monitoring a step further with its Machine Check Architecture, which monitors drives and memory for degrading function. The ProLiant 5000 monitors har d drives for soft errors, and system memory and the processor's L2 cache for single-bit errors. Compaq's NT hardware abstraction layer (HAL) provides hooks so that Insight Manager can pick up on problems, and its Prefailure Warranty covers replacement before parts actually fail.

ALR's Revolution Quad6 offers more expansion room than Compaq's ProLiant 5000, similar performance, and a set of reliability and security features somewhat less sophisticated than the ProLiant's, but at a price that's around $2500 lower for a comparable configuration. It's a large, wheeled, double-wide unit with plenty of space for storage devices and a unique front-mounted touchscreen LCD panel that displays the status of critical hardware. The panel, which you can easily use without instructions, includes monitoring for CPU status, RAM status, hard drive activity, fan rpm (all 12 of them), temperature (four processors and ambient case temperature), voltage levels at key points on the system board, hardwar e locks, and system firmware and BIOS.

The motherboard occupies the right half of the system, and the 11 5-1/4-inch drive bays and power supplies fill the left side. Our test unit had dual 575-W power supplies. The two side-access panels secure with locks. Locking snap-shut doors cover the drive-bay area, and the hot-plug drive cage has its own lock. With eight PCI and eight EISA expansion slots (one shared), the system board is large. The four processors mount in zero-insertion-force (ZIF) sockets for easy upgradability, and the single memory card, held in place with metal braces, takes up to 2 GB of SIMMs. Ours came with 256 MB of 60-nanosecond memory.

The system we tested came with three 2.15-GB, 7200-rpm Conner Fast-Wide SCSI-2 3-1/2-inch hard drives mounted in the hot-swap cage and attached to a single-channel ALR Adac RAID caching controller with 8 MB of cache memory. (We configured it as three separate unstriped volumes for testing.)

We found the LCD panel useful when we first started the Quad6. The system emitted a loud, high-pitched tone when we turned it on. It booted properly, however, so the problem was not readily apparent. The panel allowed us to disable the alarm sound and indicated a faulty power supply. An examination inside the system revealed there were two complete identical power systems, powered from two electrical jacks (one was hidden by a sticker). Plugging in the second cord fixed the problem.

In our SQL Server performance testing , the ALR machine provided processor/memory performance identical to the ProLiant's. Its reliability features aren't quite as robust as the ProLiant's, but given the price difference and greater expansion room, you may find the Revolution Quad6 the best deal of any quad-Pentium Pro server.

The Compaq ProLiant 5000 arrived with a seven-bay drive cabinet ($1229) of almost the same size as the ProLiant itself, though it didn't have to. The four hot-pluggable drives could all have fit in the m ain system. Instead, two drives occupied each cabinet. Combined, this provided comparable space to the ALR system alone. The two cabinets connected with a single SCSI-2 cable attached to a Compaq Smart-2 Array Controller/P PCI card. By connecting multiple drive cases to the ProLiant, you can store up to 361 GB on hot-swappable hard drives.

The tested system included 256 MB of 60-ns dual in-line memory modules (DIMMs) protected by the ECC functionality provided by the 82450 chip set. The chip set calculates the 8 ECC bits necessary for 64-bit data and stores them in the parity bits in parity memory. Thus, you don't have to pay more for actual ECC memory modules. The ProLiant's twin memory cards hold a maximum of 2 GB and will be able to hold 4 GB when larger DIMMs become available.

The system board incorporates a dual, peer PCI-bus architecture with seven PCI slots and three bridged EISA slots (two shared). The ProLiant 5000 incorporates a bus-utilization monitor for examining bus traffic on the tw o PCI buses and will warn of suboptimal bus loading.

The four 200-MHz Pentium Pro processors were paired on two 64-bit CPU cards. The CPU cards are mounted in the system with physical support from a removable metal mounting bracket, which ensures that the cards are installed and positioned properly. Each card supports two CPUs, along with up to three power modules for regulating power from the power supply to the CPU. The third module ($295) is redundant. It can switch over to either CPU if needed.

You can add a redundant voltage-regulator module (VRM) to back up the modules that regulate system-board voltage should they fail or go out of tolerance. The system can map out a failed CPU and work without it, and should the boot processor fail, any of the remaining three CPUs can take over as the boot processor. If you install a second Compaq Ethernet card, it can act as a backup that takes over without data loss in case of a failure in the primary network interface card (NIC).

Compaq includes a software installation package called SmartStart. By booting a new system with the SmartStart CD, you can select the desired OS (NT, NetWare, or SCO Unix), and that OS will be installed and the system optimized for its use, although the optimization won't be as good as that performed by an experienced system administrator.

With performance equal to the Revolution Quad6 with our test configuration, the ProLiant 5000 must justify its higher price with its reliability features and Compaq's support. For applications requiring high availability, that may be enough.

Scaling Up

Our testing with SQL Server (see the sidebar "Testing SMP with SQL Server 6.5") showed no significant differences between the two systems, which is not surprising given the architectural uniformity dictated by Intel's 82450 chip set. We tested the Revolution Quad6 with one, two, three, and four processors enabled, and found that SQL Server performance scaled up nicely under NT 3.51.

For logistics reasons, we tested pure CPU and memory performance under SQL Server and not the capabilities of the mass-storage or network subsystems, which should lead to performance differences depending on the test and what options you pay for. For those companies that have put the substantial time and resources necessary to stage official TCP-C database tests, you can compare their published results on the TCP Web site ( http://www.tpc.org ).

For truly large applications, memory configuration is an important performance factor. According to Compaq, its high TCP-C results with the ProLiant 5000 would have been substantially lower if they had tested with only 1 GB of RAM. The extra 1 GB allowed for more data caching. Also, at these high memory capacities, Compaq claims an advantage in its DIMM-based architecture. You can't go much high er than 2 GB with SIMMs, because it requires twice as many modules as with DIMMs; you run into mechanical form-factor constraints and increased capacitive load with longer traces, additional buffers, and the 5-V technology needed with SIMMs. (DIMMs are 3.3-V parts.)

In addition, you may not get as good performance at 2 GB with SIMMs as with DIMMs, because the SIMMs' higher capacitive load should create sloppier bus timing that may force the BIOS engineers to set the Pentium Pro's tuning registers for memory timing to use more wait states with high memory capacities. In this regard, ALR is developing a DIMM-based memory card.

Both the ALR and Compaq servers are capable, well-engineered machines with extensive feature sets. Choosing between them comes down to a balance of price versus server availability. If price and expansion capacity are more important to you than high availability, ALR's Revolution Quad6 is the system of choice. But if high availability is critical, price becomes a lesser factor, and that is where the ProLiant 5000's more sophisticated reliability features gain the edge.

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Where to Find

Advanced Logic Research, Inc.

Irvine, CA
Phone:    (800) 444-4257 or (714) 581-6770
Fax:      (714) 581-9240
Internet: 
http://www.alr.com


Compaq Computer Corp.

Houston, TX
Phone:    (800) 345-1518 or (713) 518-1442
Internet: (
http://www.compaq.com


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ALR Revolution Quad6 Ratings

Advantages

+ Lower price
+ Generous expansion capabilities
+ Informative LCD front panel


Disadvantages

- SIMM memory


Ratings

Technology     *****
Implementation  ****
Performance    *****

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Compaq ProLiant 5000 Ratings

Advantages

+ Highly developed hardware diagnostics
+ Prefailure diagnosis and warranty
+ DIMM memory


Disadvantages

- Higher price


Ratings

Technology     *****
Implementation  **** 
Performance    *****

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Pentium Pro Server Features

                          
ALR Revolution Quad6
        
Compaq ProLiant 5000


Processor/Memory

CPUs                      Four 200-MHz Pentium        Four 200-MHz Pentium Pros
                          Pros (512 KB of buil
t-in L2 (512 KB of built-in L2 
                          cache memory)               cache memory)
Motherboard design        ALR                         Compaq
Intel PCI chip set        82450GX                     82450GX
RAM as tested/maximum     256 MB/2 GB                 256 MB/2 GB 
 (speed, package)         (60-ns SIMMs)               (60-ns DIMMs)
Memory bus width/speed    256 bits/66 MHz             256 bits/66 MHz
Memory interleave (as     Four-way                    Four-way
  tested with 256 MB 
  of RAM)

Mass Storage

Hard drives               Three 2.15-GB, 7200-rpm     Four 4.3-GB, 7200-rpm 
                          Fast-Wide Conner            Fast-Wide Seagate 
                          CRX2000D72 SCSI drives      ST15150W Barracuda 
                          in ALR internal Smart       SCSI drives in hot-swap 
                          Quick Hot swap cage modules (two in ProLiant, two 
                                                      in external cabinet)

Drive controller tested   ALR Adac one-channel PCI    Integrated 32-bit 
                          SCSI RAID controller        dual-channel Fast-Wide 
                          (8 MB of cache memory)      SCSI-2 controller and 
                                                      Smart-2 Array 
                                                      Controller/P (4 MB of 
                                                      cache memory)
Drive test configuration  Three physical volumes      Four physical volumes 
                          (no RAID)                   (three used, no RAID)
CD-ROM drive              4XIDE                       4XSCSI-2
Hard drive bays           11 5-1/4-inch bays (two     Four 3-1/2-inch hot-plug
                          used by three-drive hot-    bays; three 5-1/4-inch 
                          swap cage for 3-1/2-inch    bays (two taken by floppy
                          drives)                     and CD-ROM drives)
Total storage capacity    32 GB with 15 ho
t-pluggable 17.2 GB internal, 361 GB
                          3-1/2-inch drives           in external cabinets 
                                                      with hot-pluggable 
                                                      4.3-GB drives

Expansion Interfaces/Ports

Expansion slots           Eight PCI (dual, peer PCI   Seven PCI (dual, peer PCI
                          buses), eight EISA (one     buses), three EISA (two 
                          shared)                     shared)
Built-in SCSI             None                        Integrated PCI Fast-Wide,
                                                      internal and external
Serial/parallel           Two/one                     Two/one
  (IEEE-1284)
Internal EIDE             Primary and secondary       None
Graphics card/RAM         Paradise Bali 64 PCI/2 MB   Integrated Cirrus/512 KB

Networking

Network card              ALR E-Net 32/110 Fast       Compaq NetFlex-3 Fast
 
                          Ethernet PCI card           Ethernet PCI card
                          (Cogent EM110)

Reliability/Security

Power supply              575-W supply with optional  488-W supply (redundant 
                          575-W redundant supply      power-supply upgrade 
                          (installed) with load       available)
                          sharing and dual cords
ECC protection            System bus and memory       System bus and memory
Hardware failure          Temperature, fans,          Temperature, fans,
  detection/notification  CPUs, power                 CPUs, power
Prefailure notification   None                        Drives, memory, processor's 
                                                      L2 cache memory
Other reliability         None                        Optional redundant voltage-
  features                                            regulator modules, built-
                                                      in fail-over with s
econd
                                                      network card, fail-over
                                                      on boot processor
Security                  Locking cabinet, BIOS       Locking cabinet, BIOS
                          passwords, open cabinet     pass-words, open cabinet 
                          notification, keyboard      notification
                          disable switch

Pricing/Support

Price (as tested)         $32,514                     $35,000 (projected street
                                                      price with external drive
                                                      cabinet)
Included software         Windows NT 3.51, SQL        Compaq SmartStart 
                          Server 6.0 (tested with     configuration software
                          6.5), and ALR InforManager  with Insight Manager
Lifetime technical phone  Yes (M-F, 6-6; Sat., 7-1)   Yes (24 hours every day)
  support
Warranty
                  Five years on system        Three-year on-site limited 
                          components/three years on   warranty; other options 
                          labor and peripherals;      available 
                          one year on-site for $10; 
                          other options available
Inquiry number            1091                        1092

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SQL Server Performance

illustration_link (22 Kbytes)

When testing processing power with SQL Server 6.5( left ), similar architectures in the two test sytems led to nearly identical performance. Test is CPU limited.

Running a processor-intensive ben chmark ( right ) with SQL Server 6.5 under Windows NT 3.51 on the ALR Revolution Waud6, performance scales up almost perfectly as more CPUs are brought into play.

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ALR Revolution Quad6

photo_link (27 Kbytes)

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Compaq Proliant 5000

photo_link (29 Kbytes)

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Dave Rowell is a BYTE technical editor who handles hardware reviews. Peter D. Varhol is chair of the graduate computer science department at Rivier College in Nashua, New Hampshire. You can reach them on the Internet at drowell@bix.com and pvarhol@mighty.riv.edu , respectively.