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Server Construction That Replaced Mainframes Still Effective

svrcnCorporations are moving to multiprocessor servers from two directions. Some are stepping down from outdated and expensive mainframe environments, while others are stepping up from the slightly souped-up PCs they’ve been using as file servers.

Either way, buyers seek out power, scalability and fault tolerance, though not necessarily in that order.

“Super” servers flex their multiple processors in one of two architectures. Asymmetric multiprocessing dedicates each processor to a specific task. In symmetric multiprocessing, a more advanced and costlier technology, tasks are distributed to whichever processor is available. This makes their hard drives easier to recover in general.

But some network operating systems, most notably Novell Inc.’s NetWare, do not support more than one processor. So compatibility with network operating systems is as important to super-server buyers as multiprocessing power is.

As part of its conversion from an IBM 4381 mainframe to a networked-PC environment, The Dr. Pepper Bottling Co. of Texas has purchased the first of what promises to be several Advanced Logic Research Inc. (ALR) SMP PowerPros, according to Chris Rodriguez, director of management information systems.

The Irving, Texas, soda-manufacturing company bought the initial PowerPro 486/50 server to run a Unix application that tracks time and money spent on the upkeep of vending machines.

Additional servers will be integrated in a combined NetWare and The Santa Cruz Operation Inc. SCO Unix network on Ethernet as downsizing from the mainframe continues, Rodriguez said. SCO Unix supports symmetric multiprocessing.

The ability to do symmetric multiprocessing was “a definite issue. That’s why we chose SCO,” he said.

“Right now [the PowerPro] has just one processor, [but] as we bring more applications across we’re going to add a second processor,” Rodriguez said. “SCO Unix was a strong consideration because it allows you to take advantage of both processors.” Like super servers from a number of other manufacturers, ALR’s multiprocessor machines come with one CPU and slots to accommodate additional processor boards.

Multiprocessing became important for Byer California after the manufacturer of women’s garments moved from a proprietary Prime Computer Inc. shop to the client/server environment of Oracle Corp.’s Oracle relational database-management system.

“We found Oracle ran moderately well on a uniprocessor but was built to run better in a multiprocessing environment,” said Michael Higgins, technical support manager for the San Francisco firm.

The firm chose two Symmetry S2000/750 servers from Sequent Computer Systems Inc. as the servers for Oracle. Byer California also relies on several other Sequent servers, like an S2000/250 that acts as a Network File System server for the company’s native TCP/IP network.

For other buyers, the need to store vast quantities of data led to the purchase of super servers.

At SaTo Travel, a nationwide travel agency based in Arlington, Va., the “super” part of its Tricord Systems Inc. PowerFrame server is its ability to plug in 10G bytes of disk storage, according to Keith Venzke, manager of SaTo settlement plan administration.

The firm needs to store two years of detailed ticket-sales information; its old Network Connection Inc. Triumph TNX server could hold only a year’s worth of stripped-down data, Venzke said.

On the PowerFrame, he said, “I’m storing in excess of 32 million records on-line and I’m doing that without a mainframe or a minicomputer. I’m storing every ticket sold, every ticket refunded, every ticket reissued for the last two years. I have $2 billion in sales at a detailed level on-line.”

SaTo users access the information, stored in several Clipper databases, to answer customer and airline billing questions.

Keyport Life Insurance Co. of Boston also looked to super servers to meet its storage needs and to serve its large group of users.

Leslie Laputz, vice president of information services, said the company initially moved its policy administration system from an IBM 3090 mainframe, whose time it was renting from a vendor, to a 386-based file server from Acer America Corp. The 386 effectively handled the initial conversion of 6,500 policies, but wouldn’t be able to keep up with the company’s larger strategy, Laputz said.

“Our future plans were to convert 120,000 policies. We realized that [the 386] was not going to cut it,” said Laputz. He explained that those plans included adding more than 100 users to the roughly 10 then on the 386 server. Testing proved the 386 unsuitable.

“The 386 slowed to its knees when we tried to put multiple stress tests on it. We looked for [a server] with more throughput and settled on NetFrame [Systems Inc.’s NF 300].”

The NF 300 has since been upgraded to a more powerful NF 450FT.

Laputz said one NetWare network connects to each of the server’s eight I/O processor boards (IOPs) — NetFrame’s proprietary application processor boards. Each of the networks therefore can read the same files and the same disk, he said.

“[The IOPs] allow us to construct eight networks into the same box,” Laputz said. “It spreads the loads such that one network does not become saturated.”

Keyport Life has recently added an NF 400 server as part of a testing system for new applications, and has plans for more super servers, Laputz said.

“We have another 10 file servers, 386s,” he said. “We have ideas of consolidating a couple of those into a NetFrame.”

The scalability of multiprocessor servers is another major selling point. The ability to add processors and huge amounts of RAM and disk storage as databases grow and LANs expand constitutes a fundamental aspect of what makes the servers “super.”

In addition to upgrading his NF 300 to an NF 450FT, for example, Laputz said he has dramatically increased the memory and disk space of his server.

“At the beginning we had 64M bytes of RAM. [We increased] that to 128M bytes, and now we have plans to put 64M bytes on top of that,” he said. “We [initially] had 2G to 3G bytes of storage, and now we have 20G.”

In choosing the Sequent servers, Higgins at Byer California said he wanted a “very scalable, cost-effective open system.

“With the Prime environment, every time a new machine came out, it usually added 25 percent more power and it cost a good deal of money,” Higgins said. “We’d roll out the old, roll in the new and we’d pay for it.

“With Sequent I can double, then double again, and double again its resource capability. I can keep adding more memory boards, more CPU boards, more disk controllers to [achieve] a level of unsurpassed performance,” Higgins said.

Approaches to scaling up for the future differ from user to user. Venzke at SaTo Travel said he’ll continue to upgrade his one Tricord server to handle his growing file load, rather than spread it over several servers. He expects that this will simplify maintenance.

But Dr. Pepper’s Rodriguez has the opposite view; he’s planning to support multiple servers. “The reason we’ve chosen to go with multiple servers instead of one huge box with eight or 10 processors is primarily to keep away from a single point of failure,” he said.

The fault tolerance many multiprocessor servers offer can ease some of that anxiety. Features like Redundant Arrays of Inexpensive Disks protect against data loss by mirroring or duplicating data. Some multiprocessor servers also offer drives that, if a problem occurs, can be removed and replaced without bringing the system down.

One buyer even said he ranks fault tolerance ahead of system performance as a buying criterion.

“The fact of the matter is, yes, they’ve got I/O performance enhancers, but the reason we bought them is not so much performance but fault tolerance,” said Mitchell Green about the Compaq Computer Corp. Systempros that the Cambridge Savings Bank of Cambridge, Mass., has purchased over the past two years.

“I know there are faster servers out there, but we bought [the Systempros] mainly because of the [Intelligent Disk Array] controls,” added Green, the bank’s assistant vice president of information systems. The Systempros’ IDA controllers protect data by mirroring it or striping it over several disk drives.

The bank has four Systempros: one model 386-420, two 386-840s and one 486-840. All four are on a WAN that connects three of the bank’s locations. The three 386 servers, which run on NetWare 3.11, handle office automation and proprietary banking applications. The 486 server runs an item-processing system on SCO Unix.

Fault tolerance was crucial because the bank relies on a small information-systems support staff, Green said.

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