Partitioning bonanza: Unix servers

Partitioning, a technology used in mainframe computers, is making its way into mid- and high-end Unix systems where corporate users employ it to isolate and protect applications from each other, combine processing power to run large applications or consolidate processing onto bigger machines.

In the next year, HP, IBM and Sun each will introduce more machines that can be divided into partitions for running different operating systems, applications and workloads. Lightweight Internet applications, such as Web serving, caching or load balancing, could be intermixed with heavier transaction-based applications such as Oracle on the same machine, saving IT the expense of buying two servers - one for each application.

In partitioning, a server's resources - CPU, memory, I/O, interconnects and buses - are divvied up according to the needs of the applications running on the server. Applications are protected from the actions of other applications that could cause failures, and optimally, they can shift allocated resources on the fly without taking the system down.

In an economy where money for new equipment is becoming scarce, companies are saving by consolidating applications onto fewer larger, more powerful machines. Partitioning helps because it lets users run separate workloads on the same machine.

"Partitions are primarily used for segregating programs, data safeguarding and data recovery. [Without partitioning,] if you have one big partition and any part of it fails, or some of the critical operating system data or configuration becomes corrupt, the whole system is down and recovery is more time-consuming and difficult," says Dan Gahlinger, senior network engineer and system administrator for Interlynx, an ISP in Hamilton, Ontario.

Gahlinger has a variety of Sun workstations and servers, including Sun's entry-level Enterprise 450 Server, that are partitioned in what Sun calls Dynamic System Domains, meaning resources can be reallocated to other applications.

Partitioning is used not only to combine operations that formerly ran on different servers, but also to run applications that have become too large to run on one processor.

"We'll be running PeopleSoft 8 with an Oracle database engine in four partitions - [the partitions] contain Web server, application server, database server and test and development," says David Meacham, director of IT for Delaware North Companies, a concessions and hospitality company in Buffalo, N.Y.

"We are replacing an HP V-Class Enterprise Server V2250 and an HP K360 server with [HP's] Superdome," Meacham says. "We looked at buying several machines, but because of the size of our database, we needed to have 24 processors for PeopleSoft alone. We didn't feel comfortable bringing in systems where capacity had already hit the ceiling." Superdome is HP's high-end PA-RISC based server.

Analysts say one promise of partitioning is its ability to adjust workloads across processors as they change.

"The more that workloads are Internet-driven and harder to predict, the more dynamic they need to be," says Jean Bozman, research vice president for IDC. "You need to have resources that can be tapped and available, rather than going out and building tremendous data centers with unlimited spare capacity."