[ Go to September 1997 Table of Contents ]|
-- by Art Brieva
If your departmental servers are running out of steam, don't lose faith: Robust quad-processor servers running Windows NT can re-energize your databases, intranets and messaging systems. At least, that's what the Microsoft Marketing Machine and a slew of server vendors want you to believe.
Eager to separate fact from fiction, we examined two of the industry's latest quad-processor Intel Pentium Pro servers: the Dell PowerEdge 6100 and the Intergraph InterServe 660. We wanted to look at these servers for several reasons. As you might recall, we tested the Dell PowerEdge 4100 (a dual-processor server) in our June issue and were impressed with its bang for the buck. By reviewing the Dell PowerEdge 6100 this time around, we can give you a true indication of NT's scalability when jumping from two processors to four. Similarly, we tested the InterServe 660 because we're already quite familiar with Intergraph's lower-cost InterServe 650-a dual-processor system that drives our Web site.
Our testing procedures
For this review, WinLab built a network containing 20 workstations running a mix of Windows 95 and NT Workstation. Each workstation had at least 32MB of RAM and a 66MHz Intel Pentium processor. We linked the test servers and 14 of the 20 workstations to a collapsed backbone network anchored by a 100BaseT shared hub. The shared hub had a downlink to a 100BaseT Bay Networks 28115ADV 10/100 switched hub hosting the remaining workstations. This combination of processing power and network bandwidth ensured that we could truly test the Dell and Intergraph servers to their limits.
We examined server performance using Dynameasure for SQL, a capacity and performance measurement tool from Bluecurve of Oakland, Calif. (see sidebar "Benchmark Procedures")
We used Dynameasure for SQL, Microsoft SQL Server and a 600MB data set to test each server's online transaction processing (OLTP) capabilities. Our test data set simulated a data warehouse order entry system with mixed reads and writes, and let us measure the number of transactions per second (TPS) at the server. We also measured the average response time (ART) it took for a given transaction to occur.
Each server was configured from scratch with Windows NT Server 4.0 and Service Pack 3. The four disks on each server were configured in one logical array with RAID level 5 and several partitions: a 50MB FAT, a 2GB NTFS for the network operating system, and a 12GB NTFS partition for the file services tests and the SQL database.
Dell PowerEdge 6100
Dell's mighty PowerEdge 6100 enterprise server is a tower-based chassis that's built like a tank. It's big, heavy (100 pounds) and rolls around on wheels. The server has two sections that are revealed when you remove the covers from either side. One side stores the disk drives and redundant 700-watt power supplies. The other side of the server stores the processor boards, I/O slots and redundant fans. Unlike the InterServe, these redundant fans can't be hot swapped. Also, the Dell 6100 will run fine on just one 700W power supply (the redundant power supply we were provided with is optional). The InterServe requires at least two of its three 700W power supplies to be working.
Accessories. The PowerEdge 6100 has four 200MHz Intel Pentium Pro processors with 512KB of level 2 cache each. Two processor boards (each board contains two processors) and a memory board plug into the main system board. The memory board has 14 DIMM slots that support up to 1GB of ECC (error-correcting code) memory. PowerEdge comes with two embedded Ultra Fast Wide SCSI controllers, two serial ports and one parallel port. There are six PCI slots and four EISA slots available for expansion. An Intel 82557 PCI 10/100 Ethernet card and an American Megatrends MegaRAID controller (Dell calls it the PERC-for Power Edge Raid Controller) fit into two of the PCI slots, and an Intel network management card fits into an EISA slot.
The MegaRAID controller used by the PowerEdge is also used in the InterServe. The only difference is that the PowerEdge has 32MB of cache on-board (upgradable to 128MB) and battery backup for the cache; the InterServe has 8MB of cache (though we upgraded to 32MB) and no battery backup. The PowerEdge's MegaRAID controller and battery occupy almost two PCI slots.
The drive bays located at the front of the PowerEdge store up to six hot swappable drives and support up to 54GB of disk space. We were provided with four 4.3GB hard drives made by Western Digital Corp. The WD 4300 Ultra Fast Wide drives have an average seek time of 8ms. LEDs are clearly visible to let you determine the status of a drive. By contrast, the InterServe's LEDs are difficult to see unless you open its drive bay.
Dell, like many other server manufacturers, bundles Intel's LANDesk to manage the entire unit as a whole. But the more we use LANDesk, the less impressed we become with it. On the upside, LANDesk allows you to monitor temperatures and voltages, reboot the server from a remote console, control the server remotely or view POST from afar. On the downside, we've found LANDesk unreliable for managing our own internal network and have since switched to WhatsUp Gold from Ipswitch.
The PowerEdge 6100's network management capabilities are practically identical to the InterServe 660's-only Dell supports fewer features. Unlike Intergraph, Dell doesn't offer memory monitoring software to manage ECC statistics.
Dell offers a three-year warranty, with one-year on-site service for parts and labor. The on-site service is provided by Digital Equipment Corp., which is known for its impressive 24/7 support.
Performance. The PowerEdge 6100 performed well without any tweaking. It offered 459.886TPS with an ART of 0.037; both marks were slightly better than those of the InterServe 660. Also of note, our client/server SQL tests indicated that NT and SQL Server scale about 30 to 40 percent higher when you move from a dual-processor PowerEdge 4100 to the quad-processor PowerEdge 6100. That means it's cost effective to buy a quad-processor NT server, rather than two dual-processor systems.
Intergraph InterServe 660
At first glance, the Intergraph InterServe 660 and 10U glossy black rack-mounted cabinet (approximately 3 by 2 by 3 feet) look really impressive. However, the bulky InterServe 660 is a tight fit in the cabinet. Once we slid an optional Deltec UPS into the bottom of the rack, there was no room for an additional expansion drive chassis or even a tape backup system. If you seek more expansion room, Intergraph's 40U rack-mounted cabinet (at more than 6 feet tall) is a wiser choice.
The system we tested came with 128MB of RAM (it supports up to 4GB of ECC memory) and, like the Dell server, it has four 200MHz Intel Pentium Pro processors with 512KB of level 2 cache per processor. The server's innovative architecture offers a whopping 11 PCI expansion slots and enhances I/O throughput by distributing I/O devices across multiple buses. For added reliability, the server uses three redundant 550W power supplies that can be removed from the back of the server on the fly. Similarly, there are three redundant hot-swappable cooling fans at the front of the server. Also included is a floppy disk drive with two integrated PC Card slots, an integrated Ultra Fast Wide SCSI controller, an 8X CD-ROM drive, Intel's 32-bit 10/100 Ethernet network card, two DB-9 serial interfaces and a parallel port. For video buffs, the server offers the Matrox Millennium chipset with 2MB of Windows RAM (WRAM)
Disk subsystem. The disk subsystem begins with the same American Megatrends MegaRAID Ultra Fast Wide SCSI controller used by the PowerEdge. It has three SCSI channels and 8MB of cache, compared to the 32MB of cache on the Dell version. This controller is the de facto industry standard for SCSI RAID. The RAID manager can be accessed from BIOS or from a GUI utility for Windows NT called MegaRAID. RAID levels can be changed from RAID 5 to RAID 0 on the fly. The manager can also change from write-back (that is, the controller reports completion even though data is still in memory) to write-through caching. We found this very helpful when tweaking the server to optimize performance for certain applications. Also, disks can be added to logical drive configurations. This capability lets you increase a drive's volume without reconstructing the entire logical drive array. The eight internal hot-swappable disk drive bays can support up to 72GB of internal disk storage. Intergraph uses Seagate Barracuda 4LP Ultra Fast Wide SCSI disk drives, which have an average seek time of 8.8 milliseconds.
Administration. The InterServe 660, when fitted in the 10U rack-mounted cabinet, can be difficult to administer. Intergraph provides poor wire-management tools, and Phillips screws (rather than simple thumbscrews that offer quick access) secure the server's cabinet. Once you remove the Phillips screws, you can pull the server out of the cabinet and support it on the cabinet's railings.
From the front of the server, you can easily see the redundant fans and management LCD. A drive bay door (secured with a key) opens to reveal the disk drive bays. The same key turns on or resets the server. At the back of the server, the redundant hot-swappable power supplies sit next to each other, and, of course, all of the various ports (keyboard, mouse and so on) are available.
Management. The InterServe 660 offers extensive management capabilities, but alas, the management features aren't integrated. For example, you must launch different applications to monitor different portions of the server.
Like Dell, Intergraph bundles Intel's LANDesk to manage the entire unit as a whole, but it also offers additional management features. On the front of the InterServe 660, an LCD panel monitors the RAID controller, temperature and voltages. Intruder detection is also supported, and the Intergraph checks for system board and firmware revisions. If a problem is detected, the server beeps loudly, but it doesn't offer a native paging system. It can link to LANDesk's paging software, but we don't consider LANDesk reliable.
Support. The InterServe line is backed by a three-year, 24/7 warranty. Parts and labor are provided within two days. We've used Intergraph support on numerous occasions. Each time, the company responded rapidly to our server issue.
Performance. When we first tested the InterServe 660, the results weren't too impressive.
While we were monitoring the SQL tests with Windows NT Performance Monitor, we noticed that the disk channel was the major bottleneck. Performance Monitor was showing very high utilization of the disk queue, but the CPUs weren't being pushed to their limits. After careful consideration, we discovered a configuration oversight on our part. By default, the RAID array was set to write-through caching, while the Dell PowerEdge was configured for write back by default. We changed the InterServe's RAID configuration and retested the system. The results were startling.
The server offered 274TPS with an ART of 0.046. That's an impressive performance improvement, considering our modification took only a few seconds. However, there's a good reason why the InterServe 660 isn't preconfigured with write-back caching. Specifically, the server doesn't have a battery backup for its cache. If the server crashes, data that hasn't been written to disk could still be in cache and lost forever if not backed up by an optional battery. The Dell PowerEdge 6100 RAID controller does include battery backup, and therefore it configures by default with write-back caching enabled.
Naturally, we wondered how much higher we could make the InterServe 660 scale with only a nominal upgrade. We upgraded the cache memory to 32MB (to ensure an apples-to-apples comparison with the Dell PowerEdge 6100) and tested the system again with write-back caching enabled. The server received a maximum of 442.236TPS with an ART of 0.057. The Dell PowerEdge 6100 maintained a slight performance advantage with its 459.886TPS.
And the winner is ...
The Dell PowerEdge 6100 and Intergraph InterServe 660 are very evenly matched. Each system offers solid performance, but Dell-once again-offers incredible bang for your buck. If Dell would improve its server management offerings, the PowerEdge series could truly give industry leader Compaq a run for its money.
By contrast, the InterServe 660's engineering is top-notch, but Intergraph has cut a few minor corners. For instance, there is no documentation for building the rack-mounted cabinet, and the CD-ROM drive is not bootable. Of course, if Intergraph were to match Dell's price, such shortcomings would be easily overlooked.
SIDEBAR: Benchmark Procedures
WINDOWS Magazine performs head-to-head server reviews quarterly. The reviews appear in the NT Enterprise Edition's March, June, September and December issues.
Our technicians perform these reviews in WinLab using Dynameasure 1.5 Enterprise and Dynameasure for SQL, two performance measurement and capacity planning tools from Bluecurve of Oakland, Calif.
Bluecurve's software loads an agent onto each workstation. This agent can launch multiple "motors" or "clients" on each workstation to increase the server's workload. For example, if each of 20 workstations runs five motors, we're essentially simulating a 100-user network. The motors execute transactions and monitor how many transactions have occurred on each workstation. Motors can be applied incrementally (for instance, we can simulate a 40-, 60-, 80- or 100-user network), which helps us determine a server's maximum throughput.
Information about Bluecurve and Dynameasure-including a free downloadable version of Dynameasure-are available on Bluecurve's Web site at http://www.bluecurve.com, or call toll-free at 888-258-2878.