Migrating Linux Applications from X86 to IBM Power Systems a Discussion of Best Practices

IBM Systems and Technology Computer Services Technical White Paper

Migrating Linux applications from x86 to IBM Power Systems A discussion of best practices

Executive summary Contents With IBM® Power Systems™ servers and blades based on the IBM POWER® processor architecture, IBM has significantly elevated 1 Executive summary system performance, throughput and resiliency. These servers are capable of running your choice of operating systems (Linux, IBM AIX® and 2 Best practices for workload IBM i) in whatever combination you choose. Most importantly, the new selection architecture also integrates IBM PowerVM® virtualization to provide 6 Best practices during extreme scalability, flexibility and robustness.1 As a result, enterprise workload migration workloads deployed in PowerVM virtual machines (VMs) not only run faster on POWER-based platforms, but they can also scale further and 6 Capabilities be optimized more efficiently. 6 Valuable intellectual property PowerVM is a complete virtualization solution that is integrated and 10 Conclusion packaged with Power Systems. This is a very robust implementation of virtualization developed by IBM, based on best practices learned over the course of four decades of experience with the IBM mainframe. With each new Power Systems generation, IBM continues to grow its virtualization offerings beyond just the hypervisor, using features such as Live Partition Mobility and Active Memory Sharing. Reducing costs, improving service and managing risk are three focus areas virtualization customers are interested in. Deploying virtualization can maximize scalability to reduce IT costs. IBM Systems and Technology Computer Services Technical White Paper

While all Power Systems servers are capable of running Linux, 2 Best practices for workload selection new Linux-only servers —announced in 2012—are optimized Selecting Linux on x86 workloads to migrate to Power Systems for specific Linux-based workloads such as big data analytics, requires an understanding of the value you gain when using a industry application solutions, and open source infrastructure Power System. services. These new servers offer lower acquisition costs, while simultaneously providing more value than solutions deployed 2.1 Linux consistency across platforms on commodity x86 hardware. Best practice: Leverage Linux on x86 compatible with Linux on Power If you manage complex and energy-inefficient x86-based IBM works with Red Hat and SUSE to provide Linux distribu- server farms with each server dedicated to a single application tions that are consistent between x86 and POWER platforms. or operating environment, you can consolidate workloads, Versions of Red Hat Enterprise Linux (RHEL) and SUSE whether dedicated or virtualized, on Linux on x86. Migrating Linux Enterprise Server (SLES) are available on POWER these workloads to Linux on Power servers can help reduce simultaneously with x86, with the same package and driver costs throughout your infrastructure and improve your ability levels. IBM also provides significant differentiation with Linux to meet changing processing demands. on Power using PowerVM virtualization, extensions to Linux reliability, availability, serviceability (RAS), and performance 2 This paper details the IBM recommendations for best practices optimization. in the selection and migration of Linux on x86 workloads and 2.2 Improve performance for virtualized workloads applications to Power Systems servers. Best practices discussed Best practice: Select Linux on x86 virtualized workloads include: and migrate to PowerVM A May 2013 study from the Edison Group3 comparing ●● Optimizing performance and scalability with virtualization on PowerVM and VMware vSphere (4.1 & 5.0) PowerVM-based virtualization. of virtualized benchmark workloads shows Power Systems ●● Choosing when to migrate applications. PowerVM-integrated virtualization technology leads ●● Maximizing costs savings associated with energy, administra- x86-based add-on virtualization, such as VMware vSphere 4 in tion, licensing and maintenance, and capacity on demand. performance. Key findings from the study conclude that ●● Using IBM offerings such as the IBM Migration Factory PowerVM: and IBM Power Systems Rewards program.

●● Developing applications. ●● Performs up to 126 percent better than VMware. ●● Scales to four times more virtual CPUs than VMware The following sections provide numerous best practices and in a VM. references to additional material for your consideration when ●● Scales linearly to use all CPUs, while VMware does not. selecting and migrating Linux on x86 workloads to Linux on Power.

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It is clear from the study’s published benchmark results that Many data centers today have small, single-purpose Linux PowerVM on POWER-based platforms not only offers supe- servers. In addition to high energy costs and management rior scalability than VMware vSphere on Intel x86-based challenges, these servers are frequently underutilized yet servers, but it also makes more efficient use of system resources under-perform at peak loads. This creates both efficiency and and imposes a negligible impact on performance. Many of these user satisfaction issues. In the end, these issues cost money. advantages relate to the fact that PowerVM is built directly into Maximize the return on your IT investments (including floor the firmware of all Power Systems servers, as opposed to space and operational costs) by moving workloads from under- x86-based virtualization products, such as VMware vSphere, utilized systems onto a single, larger system. You can signifi- which are typically third-party software add-ons that are sold cantly lower operational costs with Power servers running all and installed separately. Linux applications, while others are running Linux applications alongside IBM AIX and IBM i applications. Some clients are Selecting existing workloads running on x86 servers using increasing utilization by more than 60 percent,5 eliminating the VMware for virtualization can realize significant performance need for multiple, small, single-purpose servers by running improvements and scaling with PowerVM. Up to 65 percent Linux applications on Power. performance improvement, 32 times increase in virtual processors and higher CPU utilization. In some cases, Power Systems can achieve an average investment payback period of 6.3 months6 through reduction of As you will see in the next section, when software licenses and various costs including energy, cooling and management. maintenance costs are based on number of processors assigned Realizing long-term cost savings is the result of the advanced to VMs, savings can be achieved by using PowerVM to increase features of Power Systems. Power is designed to cut costs and processor utilization with fewer processors. For example, a soft- increase system utilization while ensuring applications get the ware savings of up to 50 percent could occur when doubling resources they need—when they need it. Additional cost savings processor utilization on half the processors. can be achieved by maximizing the use of physical resources by sharing processors, memory and I/O between clients’ logical 2.3 Maximize system utilization to reduce partitions within the server. At peak time, Power Systems can system costs even borrow extra capacity from development or test partitions Best practice: Select workloads from underutilized to effectively meet demand. IBM EnergyScale™ technology x86 systems provides functions that help the user understand and control Select a Linux on x86 workload running on multiple servers IBM server power and cooling use. This enables better facility that are underutilized. In many cases, workloads running across planning, provides energy and cost savings, enables peak energy multiple x86-based servers leave the system less than 35 percent utilized.4 Consolidating these workloads to a single Power Systems server can reduce total cost by leveraging the ability of a Power Systems server to run at higher utilization levels.

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usage control and increases system availability. The client can 2.5 Learn from experience of others use EnergyScale capabilities to customize the power consump- Best practice: Select high ROI workloads based on tion of their Power processor-based system and tailor it to their experiences of others particular data center needs. IDC published results from research data and analysis demon- strating the high return on investment (ROI) of running Linux 2.4 Improve reliability, availability, serviceability workloads on IBM servers. Customers involved with this study Best practice: Select workloads based on RAS reported a total annual value of USD30,000 per 100 users for requirements benefits migrating to Power Systems and IBM System z® An IDC study of Linux workloads states “…All of these work- servers. Major contributors to the savings were: IT staff loads have high uptime requirements because any downtime productivity increase (14 percent); user productivity increase would impact user productivity and therefore business produc- (25.4 percent); and IT infrastructure cost reduction tivity.”7 We understand that many Linux on x86 workloads are (60.6 percent). Based on this study, selection of workloads considered mission-critical and migrating these workloads takes with high costs in these areas could result in substantial ROI.8 advantage of the high reliability, availability, serviceability (RAS) provided by Power Systems. 2.6 Simplify workload deployments Best practice: Co-locate applications with their database Linux on Power applications benefit from Power Systems Consider selecting workloads where the application is RAS features: running on Linux on x86, but the application’s data is located on Power. For example, SAP or web serving applications using

●● Redundant and hot swap hardware, dynamic processor and IBM DB2® with AIX, IBM i or Linux on Power. Co-location memory sparing reduces hardware elements to improve overall system ●● PowerVM provides RAS related virtualization features such availability. A virtualized network helps reduce network paths as Live Partition Mobility which allows workloads to quickly to improve both workload performance throughput and move between systems for availability and service, and virtual response times. I/O (storage, LAN) to reduce risk of failing hardware components When an application and its data cannot be migrated at the ●● Live Partition Mobility manages bringing a workload online, same time, it might be easier to start with the data servers, such as processing a weekly payroll, only when needed to allowing for your IT staff to get familiar with Power Systems save system resources and prove its value. Note that by migrating applications and ●● Capacity upgrade on demand provides try-and-buy to data in stages, a remote connection is usually required from the dynamically activate processors and memory application to the data.

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2.7 Use IBM-supported applications IBM middleware that is available on Linux that Power Systems Best practice: Use software supported by support most IBM middleware. Selecting Linux on x86 work- IBM and IBM Business Partners loads using this middleware can significantly ease migration to Some workloads stand by themselves without application Linux on Power. dependencies on middleware, or provide their own. However, when selecting applications to migrate that rely on middleware Additionally, Power Systems supports the Linux provided infrastructure from IBM or third parties, the target environ- LAMP infrastructure (PHP, Pearl and Python applications ment needs either to support the middleware, replace the mid- using MySQL with an Apache HTTP server). These applica- dleware, or stand on its merits with less. Depending on the tions and their data migrate easily to Linux on Power using the requirements, some options will be easier and more attractive IBM Installation Toolkit for Linux. than others. Sometimes functions can be staged to get a solution to market quicker, allowing enhanced functionality in 2.8 Minimize software license and maintenance costs a later release. Best practice: Select workloads with processor-based software pricing IBM and IBM Business Partners have a large number of Many workloads utilize processor-based software license and software applications and middleware available for Linux maintenance costs. Selecting these workloads to consolidate to on Power. Selecting from existing Linux on x86 workloads fewer cores on Power can maximize your software investment utilizing this software not only eases migration, but also and help speed your ROI in Power Systems. helps ensure optimal software performance and support. IBM developerWorks® provides an excellent resource for For example, in a study of consolidating a workload from learning more about applications that support Linux on Power. 41 x86 servers to a single Power server, a customer saved USD360,000 (95 percent) in software costs over a three year Starting with the operating system, IBM has worked with lead- period. The study revealed that 41 quad-core x86 Xeon-based ing Linux distributors to provide Red Hat Enterprise RHEL servers running IBM middleware require 8,200 processor value and SLES Linux offerings for POWER. These two companies units (PVUs) be purchased (41 servers x 4 cores per server x have also worked with IBM to exploit many of the Power 50 PVUs per core) for licenses and maintenance at a three year Systems features such as dynamic logical partitions (DLPAR), costs of over USD400,000. When consolidated to a single virtual I/O, application mobility and active memory sharing. Power 750, only 1200 PVUs, at cost of USD43,000, are Refer to the supported features for Linux on Power systems required for maintenance (12 cores x 100 PVUs per core) since servers page for details. You can see from the list of PVUs for licenses can be transferred between servers.9

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3 B est practices during workload Factory offers strong tools, coupled with proven methodologies, migration to achieve the comprehensive coverage of requirements within 3.1 Migrate before it is required a short period of time. Each step of the migration process is Best practice: Select Linux on x86 workloads to migrate designed to build upon the previous step and move seamlessly before it is required into the next. If you wait until you need to migrate, you have waited too long. This is true for all types of workloads, including third-party, Capabilities custom-written and database applications. Consider migrating In development over the last 20 years, many migration and workloads before a critical situation occurs, such as your consolidation capabilities have been added to the Migration workload demand exceeding current system capacities, Factory to help ensure the success of large enterprise migration data center resources becoming exhausted, software budget and consolidation projects. Migration capabilities include port- reductions, or software going out of service. ing of x86 custom code applications, databases, typical enterprise applications, such as SAP, PeopleSoft and Oracle EBS, 3.2 Plan workload migrations and middleware, such as IBM WebSphere®. Best practice: Develop a comprehensive plan Moving data requires a comprehensive migration plan that Valuable intellectual property includes budget considerations, the transition of skills, the The development of the Migration Factory has resulted in the capacity of staff and equipment, and availability to end users. creation of vast amounts of intellectual property for migration Your plan needs to cover all aspects of the migration, from and consolidation. This includes: beginning to end. How are issues like external third-party software dependencies or high availability addressed? ●● Knowledge databases that have captured years of data and experience that are used to reduce the cost and time and 3.3 Use the IBM Migration Factory expertise improve the quality of analysis. Best practice: Leverage migration expertise built over two ●● decades Tools for collecting data, migrating, remediation of code and IBM Migration Factory is a migration services offering that has testing. These reduce the time, cost and risk of helped thousands of customers migrate their workloads. The implementation. ●● Migration Factory brings extensive experience in analysis and Proven processes for each phase that provides a roadmap for implementation of platform migration projects. The Migration success. ●● Years of migration and consolidation experience.

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To help mitigate development risks, the Migration Factory While no two projects are identical, the Migration Factory process uses these best practices when migrating custom code process helps ensure that each engagement is a success whether applications.10 it is an infrastructure migration, database migration, ISV package, custom applications, or combination of all four. 1. Use tools wherever possible. There are many commercial The Migration Factory process is five steps that have been tools available for migration projects. There are standard meticulously refined over 25 years, helping clients migrate to UNIX tools, tools to convert older languages to C++ or Java, IBM Systems running any supported operating system, includ- tools to help migrate large databases with minimal downtime ing Linux. IBM provides several levels of service for the windows and many proprietary IBM tools. Migration Factory: 2. Always reuse code wherever possible, and don’t rewrite, unless necessary. If changes must be made to custom code, 1. Full service migration: IBM owns the project and client they must be documented at the completion of the migration. provides the resources to assist. Recoding is almost always a result of something working a bit 2. Migration workshop: Client owns the project and differently in the target environment than it did in the source IBM provides a workshop to assist. environment. It usually doesn’t require changes to the 3. Third party integrator: IBM will assist the client in finding a application’s business logic. migration partner. 3. Next to the initial planning of the migration, testing is one of the most critical elements for a successful migration. Leverage your Power Rewards 10 and get a free IBM Migration A formal, written test plan must be created and closely Factory “Migration Assessment.” followed. This should be a living document that is useful through the entire lifetime of the application, serving a 3.4 IBM installation toolkit for Linux critical role in everything from validating the source or Best Practice: Use IBM tools for installing and migrating to Linux on Power baseline system to providing the framework for final IBM Installation Toolkit for Linux is a set of tools, available at no acceptance testing. charge, that includes a wizard to simplify the installation and 4. Always do a “like-to-like” migration when migrating custom configuration of SLES and RHEL Linux distributions on code. Migrating applications still under development involves Power Systems. Included are over 20 IBM value-add RAS tools too much risk, as does trying to migrate an application for upgrading of firmware, diagnostics, bootable rescue DVD, currently in production and trying to add a major new feature maintenance, improving application performance, migration of at the same time. LAMP stack (Linux, Apache, mySQL, Perl, Python and PHP) and data from x86 servers, and access to over 60 Linux user documents.

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3.5 Advance Toolchain When migrating Linux on x86 to Linux on Power it may be Best practice: Use IBM-supported Linux libraries for necessary to understand several areas of application develop- performance ment associated with the differences between x86 and Power Advance Toolchain is a standalone POWER open source GNU architecture and how to address them. Minor changes and toolchain from the Free Software Foundation. IBM provides a recompile may be necessary unless the application has this cross-platform set of system libraries and tools tuned hardware-specific dependencies such as “endianness” (or byte for POWER application development that deliver better ordering), data type length and alignment. performance than the Linux distribution toolchains. 3.6.2 Compilers: GCC and IBM XL C/C++ Packages, such as GCC, glibc, gdb, oprofile and more, are Support from both IBM and non-IBM compilers and utilities optimized for all Power systems. can help address the differences between the x86 and the Power architecture. Recommendations and examples of Standard IBM Linux support includes use of the methods to address these differences are covered in articles: IBM Linux Advance Toolchain. Linux on Power: An overview for developers and Guide to porting Linux on x86 applications to Linux on Power. You can also visit 3.6 Porting C applications from Linux on x86 to the Linux for Power Architecture forum for more information. Linux on Power Best practice: Code, compile, make C applications for IBM Power By leveraging the optimization options of the compilers, 3.6.1 IBM Power architecture differences you can keep portable code performing well on both x86 and In most cases when the same release of Linux is used during Power Systems platforms. You can optimize your application migration from x86 to Power Systems, most Linux applications for performance by selecting the latest Linux kernel and simply need to be recompiled using Linux distribution compilers. provided tooling.

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IBM works with SUSE and Red Hat to help ensure their For example, IBM XL C/C++ Version 9, available for RHEL5, Linux distributions are optimized for each release of adds performance improvements for Power Systems. Power Systems. The -qarch option is used to optimize performance for Power Systems architecture. See POWER7 tolerance for IBM XL If application portability is of the most importance to you, use Compilers for POWER7 details. of GCC is recommended since it supports both x86 and Power platforms. Applications compiled with the latest versions of 3.6.3 Optimizers (FDPR-Pro) GCC with optimization level 3 (-O3) perform comparable to After porting your application to Linux on Power, consider a the IBM XL C/C++ compiler. Note that IBM XL C/C++ does final optimization step using IBM Post-Link Optimization for not support x86 platforms. Linux on Power, also known as FDPR-Pro. FDPR-Pro is a post-link optimization utility for the POWER architecture that If application performance is more critical than x86 and optimizes an executable program or a shared library, based on POWER portability, consider using IBM XL C/C++, which its runtime profile. provides more performance optimizations than GCC for Power Systems. The IBM XL C/C++ compiler for Linux on Power is 3.7 IBM Software Development Kit for PowerLinux Best practice: Use this IBM no-cost software development derived from the high performance compiler for AIX, but uses toolkit to simplify development the GNU linker and assembler to create ELF objects that are The IBM Software Development Kit (SDK) for PowerLinux is an fully compatible with objects produced by GCC. Refer to Eclipse-based Integrated Development Environment (IDE) Application optimization with compilers for Linux on Power for a available for download from the link above. The SDK provides comparison of GCC and IBM XL C/C++ compiler features, integration of important Linux and IBM tools into a single including the –O5 performance optimization level. GUI environment, such as OProfile, Perf, Valgrind, and autotools for Linux and IBM FDPR®.

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The SDK integrates C/C++ source development with the design, custom application porting, performance analysis and Advance Toolchain, Post-Link Optimization, and classic Linux tuning, virtualization with PowerVM, middleware consulting, performance analysis tools to provide you with an all-in-one implementation, training, health checking, and integration solution for developing software on IBM PowerLinux™ with IBM i. platforms. 4 Conclusion You can use the Eclipse IDE directly on the Power Systems There are many considerations to take into account when server or an x86-64 client for remote development. You can selecting Linux on x86 workloads for migration to Linux on access the SDK using a technique called X-Forwarding, which Power that can speed your return on investment. Leverage allows you to integrate the SDK interface to an interface run- PowerVM performance and scaling to consolidate existing ning on your Linux desktop. The SDK also facilitates creation workloads that use VMware, as well as workloads on under- of a virtual desktop session on the POWER server and connect utilized x86 systems to fewer systems to provide better availabil- to it using either Linux or Microsoft Windows clients. Visit ity and lower hardware and software costs. Review middleware this IBM developerWorks page to view a demo. from IBM, IBM Business Partners and third-party providers to minimize dependencies during migration and leverage the 3.8 IBM consultants SDK for PowerLinux to facilitate development. IBM also Best practice: Work with the team of IBM consultants provides tools that help port LAMP applications and data, and IBM Systems Lab Services and Training is a team of consultants optimize C/C++ applications for Power. that can help with many aspects of workload migration from Linux on x86 to Linux on Power. Consulting services are available for data center consolidation, Power Systems hardware and software, Linux on Power and more. Linux on Power consultants offer services for architecture, custom application

10 Notes For more information To learn more about migrating Linux on x86 workloads and applications to Power Systems servers, please contact your IBM representative or IBM Business Partner, or visit the following website: ibm.com/power/powerlinux © Copyright IBM Corporation 2014

Additionally, IBM Global Financing can help you acquire IBM Corporation the software capabilities that your business needs in the most Systems and Technology Group Route 100 cost-effective and strategic way possible. We’ll partner with Somers, New York 10589 credit-qualified clients to customize a financing solution to suit Produced in the United States of America your business and development goals, enable effective cash March 2014 management, and improve your total cost of ownership. Fund your critical IT investment and propel your business forward IBM, the IBM logo, ibm.com, Power Systems, POWER, PowerVM, AIX, EnergyScale, System z, DB2, PowerLinux, developerWorks, FDPR, and with IBM Global Financing. For more information, visit: WebSphere are trademarks of International Business Machines Corp., ibm.com/financing registered in many jurisdictions worldwide. Other product and service names might be trademarks of IBM or other companies. A current list of IBM trademarks is available on the web at “Copyright and trademark 1 IBM PowerVM Virtualization Technology on IBM POWER7 Systems: information” at ibm.com/legal/copytrade.shtml A Comparison of PowerVM and VMware vSphere (4.1 & 5.0) Virtualization PowerLinux uses the registered trademark Linux pursuant to a sublicense Performance, accessed at: https://www.ibm.com/services/forms/ signup.do?source=stg-web&S_PKG=us-en-po-ar-edison&S_CMP= from LMI, the exclusive licensee of Linus Torvalds, owner of the Linux mark on a worldwide basis. web-ibm-po-_-ws-powerhp 2 IBM Power Platform Reliability, Availability, and Serviceability (RAS), Intel and Intel Xeon are trademarks or registered trademarks of Intel Jim Mitchell, Daniel Henderson, George Ahrens, and Julissa Villarreal, Corporation or its subsidiaries in the United States and other countries. accessed at: http://public.dhe.ibm.com/common/ssi/ecm/en/ Microsoft, Windows, Windows NT, and the Windows logo are trademarks pow03003usen/POW03003USEN.PDF of Microsoft Corporation in the United States, other countries, or both. 3 Accessed at: https://www.ibm.com/services/forms/signup.do?source= stg-web&S_PKG=ov14937 UNIX is a registered trademark of The Open Group in the United States and other countries. 4 Robert Francis Group, “The IBM PowerLinux Advantage.” Accessed at https://www.ibm.com/services/forms/signup.do?source=stg-web& Java and all Java-based trademarks and logos are trademarks or registered S_PKG=ov9418 trademarks of Oracle and/or its affiliates.

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6 IDC Adding Business Value with Cross-Platfor m Solutions: Linux Running on It is the user’s responsibility to evaluate and verify the operation of any IBM Servers, Oct. 2008, ftp://ftp.software.ibm.com/linux/pdfs/IDC-adding_ other products or programs with IBM products and programs. business-value_with_cross-platform_solutions-Linux_on_IBM_Systems.pdf THE INFORMATION IN THIS DOCUMENT IS PROVIDED 7 IDC Adding Business Value with Cross-Platfor m Solutions: Linux Running on “AS IS” WITHOUT ANY WARRANTY, EXPRESS OR IBM Servers, Oct. 2008, ftp://ftp.software.ibm.com/linux/pdfs/IDC-adding_ IMPLIED, INCLUDING WITHOUT ANY WARRANTIES business-value_with_cross-platform_solutions-Linux_on_IBM_Systems.pdf OF MERCHANTABILITY, FITNESS FOR A PARTICULAR 8 IDC Adding Business Value with Cross-Platfor m Solutions: Linux Running on PURPOSE AND ANY WARRANTY OR CONDITION OF IBM Servers, Oct. 2008, ftp://ftp.software.ibm.com/linux/pdfs/IDC-adding_ NON-INFRINGEMENT. IBM products are warranted according to the business-value_with_cross-platform_solutions-Linux_on_IBM_Systems.pdf terms and conditions of the agreements under which they are provided. 9 Total Cost of Acquisition and Ownership Study for: Consolidating Lotus Domino x86 Workloads on IBM Power Systems, accessed at: Please Recycle http://www.itworld.com/virtualization/312398/ consolidating-lotus-domino-x86-workloads-ibm-power-systems 10 The Migration Advantage, IBM Systems magazine, December 2005, accessed at: http://www.ibmsystemsmag.com/aix/december05/ coverstory/6701p1.aspx

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