LINUX for S/390 Strategy
Executive SummaryGrowth of the Internet is enabled by standards, and IBM is seriously committed to open standards. LINUX® [ http://www.s390.ibm.com/linux/ ] is the pervasive open system standard, as such Linux is the fastest growing server operating system. It is most popular in small to midsize Intel-based PC servers. It has become a rallying point within the industry, one that will play a key role in the evolution of the next generation of e-business networks and computing. Linux is more than just another operating system. It is the product of an ongoing collaboration among the best programmers in the industry coming together to create an operating system that can work on a variety of hardware platforms.
Linux has been quite popular as the operating system for web servers, file and print servers, and various Internet access infrastructure servers, both in enterprises and in the NetGen marketplace. It is, however, on a path to becoming a viable enterprise operating system, capable of running a variety of workloads requiring high scalability and industrial strength. IBM® is an ongoing contributor to the Linux community, helping to enhance Linux's capabilities as an operating system for e-business
Linux runs natively on S/390® and Linux applications that run on other hardware can be recompiled to run on S/390 Linux. As with other S/390 operating systems, customers have the flexibility of running Linux in a dedicated S/390, or they can run multiple images of Linux on a single S/390 as virtual servers, using either logical partitions (LPARs) or VM/ESA®. No other hardware platform can offer customers the flexibility of deploying hundreds of Linux images on a single machine. This flexibility enables customers to benefit from reduced operational costs through centralization of backup and recovery and other administrative tasks.
Businesses have many server platforms from which to choose. Each server platform offers businesses a different style of computing to meet their needs. Businesses will evaluate a number of factors when selecting a hardware platform.
S/390 is well positioned to take advantage of growth in the Linux market. S/390 is the industry's most reliable hardware platform. Its self-configuring and self-healing attributes such as CPU and memory sparing, fault-tolerant cache structure, and transient error recovery have made S/390 reliability legendary. While the reliability of Linux as an operating system may be similar across server platforms, S/390 architecture will put applications running on Linux one step higher in availability.
The value of S/390 and Linux is:
Why Linux and why Open Source?
The evolution of e-business is presenting customers with a new set of challenges:
Linux is becoming a rallying point within the industry, one that plays a key role in the evolution of the next generation of e-business networks and computing. Linux is more than just another operating system. It is the product of an ongoing collaboration of the best programmers in the industry coming together to create an operating system that can work on a variety of hardware platforms.
Linux is already the fastest growing server operating system. Linux today is most popular on small to midsize Intel-based PC servers, as well as on clusters of such servers. It is very popular as a platform for modest-sized Web and e-commerce servers, ISP/ASP applications, dedicated networking functions (such as Web-infrastructure, file/print, LAN, firewall, DNS, e-mail, and so on), supercomputing clusters, as an embedded operating system for new server and client application appliances, as well as the development platform for many innovative "next generation" applications. As the robustness and capabilities of Linux are enhanced, there is a growing need for a larger-scale, more cost-effective hardware platform that can host multiple enterprise-focused Linux applications.
As a technology, Linux is developing into one of the standard development platforms for the spectrum of applications that comprise our customers' e-business solutions. Linux provides consistent operating system services across all open platforms so application can be rehosted quickly. IBM's Application Framework for e-business allows you to port applications quickly. Together they make application mobility a reality by creating an environment where applications are developed once and with minimal effort can be deployed across a broad range of servers and environments. This application mobility is essential for customers to be able to respond quickly to the dynamic nature of e-business.
The impact of Linux is that customers will be able to select independently: 1) the applications that are best suited to their business needs, 2) hardware platforms matched to their quality of service (QOS), performance and capacity requirements and 3) operating environments that impart critical characteristics to the applications. Linux is on a path to becoming a viable enterprise operating system, capable of running a variety of workloads requiring high scalability and industrial strength. IBM® is an ongoing contributor to the Linux community, helping to enhance Linux's capabilities as an operating system for e-business
Why Linux for S/390?
The Linux application portfolio will greatly increase the number of current applications available to the S/390 customer, a significant enhancement. Besides that, all of the great flexibility and openness of Linux combined with the qualities of service of S/390 results in an industrial strength Linux environment. In addition, S/390 can uniquely provide customers with the ability to consolidate a large number of servers onto a single platform easily, a "Server Farm in a Box". Also, Customers can blend the data richness of the S/390 environments with the Web capability of Linux applications to deliver a highly integrated e-business solution.
Linux offers S/390 a truly portable application environment. By using the identical source code on all platforms, a simple recompile is generally all that is required to rehost an application. S/390 is the only platform that provides the flexibility of deploying hundreds of Linux images and applications on a single S/390. These applications will benefit from the robust availability characteristics built into S/390 hardware. For e-business applications, higher availability translates directly into continuing business operation. The term availability is often abused, as every advertisement discussing an operating system uses it. Hardware that adds availability to an application must have self-healing attributes to protect an application from failure. These include computational integrity, fault tolerant cache hierarchy, transient error recovery, memory chip sparing, CPU sparing, zero outage hardware repair, and concurrent microcode updates.
No other platform can recover from failure without impact to the application as well as S/390.
Linux for S/390 or Linux on other platforms?
There are three distinct classes of servers:
So let's review the factors considered in choosing a platform and discuss each in detail.
|Net: Customers must evaluate multiple factors to choose the platform that best meets their needs. These factors, when taken together, reflect the total cost of ownership and speed of deployment.|
When OS/390 and when Linux for S/390?
As one analyst points out: "S/390 reliability is legendary, and dramatically better than can be achieved with most other systems". This reputation was not achieved by accident. IBM has developed the S/390 architecture and OS/390 operating system to run the world's most critical applications at availability levels reaching 99.999%. IBM will continue its investment in OS/390, bringing robustness and qualities of service into new interfaces and programming models. OS/390 became one of the first UNIX-branded operating systems. The UNIX® support in OS/390 has evolved into a robust UNIX application hosting environment, bringing S/390 qualities of service to important UNIX applications and middleware.
Applications and middleware ported to the OS/390 environment generally require tuning and optimization to gain optimal performance and availability characteristics expected with the highest enterprise-class qualities of service. While UNIX applications are portable to the OS/390 environment, the tuning and optimization requirement may add a level of expense which may not be necessary if it doesn't need the same mission critical qualities of service. However, e-business applications have a strong requirement for high-speed access to data residing on OS/390 transaction and database systems. Linux will complement OS/390 to meet this need.
Most e-business solutions run a two-tier architecture, namely a highly mission-critical transaction and database tier, and a highly flexible web front-end tier. OS/390 is clearly the leading platform for the transaction and database tier, and it integrates with the Web tiers in three main ways:
|Net: Linux complements OS/390 enabling rapid Web application deployment while providing rapid access to DB2, IMS, and CICS.|
Linux for S/390: Virtual Servers or Native?
Whether connecting to back-end data or consolidating scores of servers, S/390 partitioning offers customers the greatest degree of flexibility. One option is to run Linux as a virtual machine using VM/ESA. VM provides virtualization of CPU processors, I/O subsystems, and memory.
A customer running VM can have hundreds of Linux systems running on a single S/390. With VM, a customer can offer a complete Linux server environment to each of their application developers and host production systems all on the same S/390 machine. Other benefits of this hosting are:
And of course, a customer could run a single Linux operating system on the S/390. This means Linux will have complete control of the entire S/390. However, running natively does not provide the flexibility to add Linux systems for testing or additional applications.
|Net: S/390 is the most reliable and the most flexible hardware platform available. Customers can run from one to hundreds of Linux servers on a single S/390.|
LINUX for S/390 home [ http://www.s390.ibm.com/linux/ ]
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