Livin Large

Linux kernel to add big-system capabilities

The Linux operating system will be better able to support enterprise-level systems when an upgraded kernel is released by lead developer Linus Torvalds, perhaps in time for the opening of LinuxWorld on Jan. 30.

The kernel is the base of the operating system (OS) and contains its core functionality. No instructions except those handed off by the kernel are acted on by the underlying hardware. Since Linux is open to tweaks by software developers, many different configurations of the kernel can be built, but the one approved by Torvalds forms the basis of Caldera Systems OpenLinux, Red Hat Linux and other popular distributions.

Torvalds made a prerelease developers copy available at the end of 2000, and the new kernel, release 2.4, is due anytime. As with many open source code projects, no one guarantees when the next release will become available.

Dave Sifry, chief technology officer at the San Francisco Linux support group Linuxcare, is betting it will appear in time for LinuxWorld in New York Jan. 30 to Feb.2. "Its gotta happen in the first quarter. It wouldnt surprise me if it were out by LinuxWorld," Sifry said.

The release of the 2.4 kernel is widely anticipated because it is likely to double the number of processors that Linux can manage at a time. Linux kernel 2.2 is known to easily run a four-processor server, but performance falls off as it tries to move into six- or eight-way servers. Odd number releases, such as 2.3, are reserved for development and not distributed to the public.

On a multiprocessor server, the OS must juggle demands from different processors for the same data or instruction sets, Sifry said. Microsofts Windows 2000 Data Center, for example, was demonstrated last fall on a 32-processor machine, and Sun Microsystems Solaris runs Sun Enterprise 10000 systems with up to 64 processors.

"Under 2.4, Linux is solidly capable of handling four to eight processors," said Sheila Hartnett, senior technologist at IBMs Linux Technology Center in Austin, Texas. "For the e-business application segment into which Linux is moving quite rapidly, eight CPUs [central processing units] is a good fit," she said. Eight-CPU machines are quickly becoming the most common hardware configuration.

Linux is frequently used as a Web server OS, a firewall or virtual private network system, a mail server or, increasingly, a database server. The 2.4 kernel will handle more than 64,000 user IDs — will help it in those roles, Sifry said.

The capability to move beyond 64,000 user IDs or user group IDs has existed in Linux for some time. A version of Linux is ready for the upcoming Intel Itanium chip, whose 64-bit processing power moves it beyond the 64,000-name limit of 32-bit systems. But the 2.4 release of Linux will be the first time the capability of handling more than 64,000 user IDs has been included in the standard kernel. Linux frequently runs on low-cost, 32-bit Intel servers, Hartnett said.

Another improvement is the 2.4 kernels ability to manage large amounts of RAM on a server. Previously restricted to 2 gigabytes of RAM, the upgrade will let Linux handle up to 4 GB, she said.

Another area where Linux is taking on large system capabilities is its new Logical Volume Manager, which lets a system administrator "hot swap" — that is, take out a failed drive in a servers storage volume and add a new one without stopping the system. The LVM also lets the administrator repartition a set of drives to generate more storage for a given purpose, Sifry said.