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IBM Software Group

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© Copyright IBM Corporation 2005 IBM Corporation Software Group Route 100 Somers, NY10589 USA Produced in the United States April 2005 All Rights Reserved IBM, the IBM logo, AIX, CICS, DB2, IMS, iSeries, pSeries, Tivoli, Tivoli Enterprise Console, WebSphere, xSeries, and zSeries are trademarks or registered trademarks of International Business Machines Corporation in the United States, other countries, or both. Microsoft, Active Directory, Windows,Windows Server Active Server Pages, Outlook, Exchange, Visual Basic, Visual C++, Component Object Model, ActiveX, SQL Server, SharePoint and .NET are trademarks or registered trademarks of Microsoft Corporation in the United States, other countries, or both. J2EE, Java, Solaris and all Java-based trademarks are trademarks of Sun Microsystems, Inc. in the United States, other countries, or both. Gartner and Meta Group are trademarks of Gartner Inc. in the United States, other countries, or both. XAD is a trademark of PADL software Pvt Ltd. in the United States, other countries, or both. Linux is a trademark of Linus Torvalds . in the United States, other countries, or both. DiamondEdge, VB Converter and ASP2JSP are trademarks of Diamond Edge, Inc . in the United States, other countries, or both. NetCoole and J-ASP are trademarks of NetCoole Inc. in the United States, other countries, or both. Robert Frances Group is a trademark of Robert Frances Group, Inc. in the United States, other countries, or both. Debian is a trademark of Software in Public Interest, Inc. in the United States, other countries, or both. Wolcott Systems is a trademark of Wolcott Systems Group, Inc. in the United States, other countries, or both. Stryon, iASP and iNET are trademarks of Stryon Inc. in the United States, other countries, or both. Binary Tree is a trademark of Binary Tree Systems, Inc. in the United States, other countries, or both. MainSoft and Visual Mainwin are trademarks of MainSoft, Inc. in the United States, other countries, or both. Other company, product or service names may be trademarks or service marks of others.

Author: Srirama Krishnakumar

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Windows to Linux Migration Roadmap Enterprises in the quest for flexibility, better security, improved reliability, and a reduction in total cost of ownership are adopting Linux® at an ever increasing pace. While some enterprises may be sold on the idea of adopting Linux, they are unsure of how to get started. In migrating many of its servers to Linux, IBM® gained considerable expertise while accumulating a set of best practices. IBM found that a step-by-step process of starting with file/print and Web servers and moving up the value chain was the best approach. This implementation strategy allowed IBM to build Linux skills while simultaneously reaping the value of Linux. This paper provides an overview of why enterprises are moving to Linux, and provides a high-level template for migration from Windows® to Linux.

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Migration to Linux:.................................................................................................... 1 A roadmap for migration from Windows to Linux .................................... 1 Windows to Linux Migration Roadmap.............................................................................. 3 Why Migrate?...................................................................................................................... 5

Linux Provides Better Security and Reliability............................................................... 5 Linux Has Lower Total Cost of Ownership (TCO) ........................................................ 5 Linux Provides Hardware Flexibility and Choice........................................................... 5 Other Reasons ................................................................................................................. 6

A Roadmap for Migration ................................................................................................... 6 File/Print Servers............................................................................................................. 6 DNS and DHCP Servers ................................................................................................. 7 Migrate Domain Controllers ........................................................................................... 7

Windows NT Domains................................................................................................ 7 Windows 2000 and 2003 Domains ............................................................................. 8

Migrate Mail Servers....................................................................................................... 9 Migrate Legacy Microsoft Applications ....................................................................... 10

Legacy Microsoft Application Technologies............................................................ 10 Migrate SQL Server to DB2 on Linux...................................................................... 11 What If You Cannot Migrate Your Applications Immediately?............................... 12

IBM Support for Migration to Linux ................................................................................ 12 Summary ........................................................................................................................... 13

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Why Migrate? Linux started out as an open source operating system project initiated by Linus Torvalds in 1991. Linux has matured considerably since then and has proven itself to be enterprise worthy. Many enterprises have decided to migrate to Linux for the following reasons:

Linux Provides Better Security and Reliability “Security levels in Linux generally exceeded those in Windows, providing a more secure and manageable environment out of the box with significantly more functionality in terms of security integration and management.” —Robert Francis Group®, “Comparing Windows and Linux Security Head to Head,” March 2004. “When servers are down, your business suffers, and in our case, a major customer had actually complained about our reliability problems…Linux on iSeries has proved to be not only more cost-effective, but also highly reliable, which helps reduce expenditure on maintenance and management.” —Brenntag Nordic, IBM Customer Case Study[1].

Linux Has Lower Total Cost of Ownership (TCO) One of the ways Linux provides a compelling financial benefit is the elimination of the need for a Client Access License (CAL), which is the fee Microsoft charges per client to access a service on a Windows server. The CAL cost is typically in addition to the licensing cost of the server. There are no CAL fees required to access a Linux server. Large enterprises with thousands of client desktops can expect to save millions of dollars by avoiding the CAL cost. “We historically have taken the position that Linux has the same TCO as Windows. ... But organizations can make choices that shift the TCO of Linux, reducing it anywhere from 10% to 40%. We have identified five key choices, which result in the following equation: Distribution + Support + Management Tools + Software Stack + Use Case = User-Controllable TCO.” — Meta Group®, “Equating Linux TCO Requires New Equation,” April 2004.

Linux Provides Hardware Flexibility and Choice Linux is supported on all the hardware platforms supplied by IBM and many other hardware vendors. Thus, enterprises are not restricted to the “Wintel” architecture while running Linux. This flexibility translates into cost savings (through the reuse and repurposing of hardware) and better manageability (by consolidating workloads). The flexibility in hardware is coupled with the ability to run a Linux version of choice (from distributors such as RedHat®, Novell/SUSE®, Debian® etc.). “We are replacing a PC-based server farm running Microsoft Windows NT with an integrated xSeries/iSeries environment under Linux and we expect to achieve significant

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reductions in total cost of ownership…The cost savings delivered through system consolidation will be the immediate benefit of the new IBM infrastructure. The banking system from Banco do Brasil’s six European offices will run on a single iSeries in London, dramatically reducing administrative overheads and increasing efficiency.” –IT Manager, Banco do Brasil.

Other Reasons Performance, availability of ERP applications [2], readiness for On Demand capability, benefits of open source, and open standards also contribute to the overall value of Linux over Windows.

A Roadmap for Migration IBM has deployed Linux on more than 3,500 servers internally to run applications such as file/print, Web applications, security, and network monitoring. IBM took a step-by-step approach in migrating to Linux - starting on the infrastructure servers such File/Print and moving up the value chain. The following table is a recommended roadmap for migration from Windows to Linux that is based on IBM’s own experience in migration to Linux.

Windows Linux File/Print Server SAMBA/Linux DNS and DHCP Server Included in Linux Windows NT ® Domain Controller SAMBA/Linux Windows 2000 Domain Controller with Active Directory®

XAD ®, LDAP, Kerberos, Linux

Exchange® Mail Server Domino®/Linux Web Applications (IIS®, ASP®, SQL Server®)

IBM HTTP Server/WebSphere ® Application Server/DB2®/Linux

Client (Visual Basic®) + Server (SQL Server)

Java Client + DB2/Linux

By following the above roadmap, enterprises can benefit from the value of Linux while building up a skill base. This document uses the results of the following studies conducted by IBM Software Group and provides cost and time metrics for migration to serve as a guideline for budgeting purposes.

• “Linux Migration Study: Windows 2000 + Active Directory” [3] • “A Migration Study: Windows NT to Linux” [4]

It is highly recommended that you read the above studies if you need to know the technical details of migration.

File/Print Servers File/Print serving is probably the most widely used function on Windows and would be the best place to start a migration to Linux (print servers generally are not mission-critical systems in most enterprises). According to a Microsoft estimate, about 1.2 million Windows NT Servers are in use as File/Print servers. Because Microsoft eliminated

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standard support for Windows NT at the end of 2004, many enterprises are faced with the question of finding an alternative to Windows NT, with a similar problem looming for Windows 2000 servers (mainstream support for Windows 2000 will be ended June 2005). Windows uses Server Message Block (SMB), a protocol for sharing files, printers, serial ports, and communications abstractions such as named pipes and mail slots between computers. It is easy to replace these Windows servers with an Open Source alternative called SAMBA (which can be freely downloaded from www.samba.org). SAMBA provides the same functionality and uses SMB. The migration is transparent to attached client machines because the underlying protocol remains the same. IBM provides several RedBooks[5] with details on migrating from Windows to SAMBA on Linux. An IBM Software Group study [4] found that it takes about 115 minutes to migrate a Windows NT file server with 50 user directories to Linux (not including actual data because that would depend on the network characteristics and the amount of data itself). It is a fairly straightforward procedure. Most of the time was spent in making sure the configuration steps were performed accurately.

DNS and DHCP Servers DNS (Domain Name Server) and DHCP (Dynamic Host Configuration Protocol) are network infrastructure functions that are already included in both Windows and enterprise Linux servers. Migrating these functions from Windows to Linux merely involves transferring the information contained in the Windows servers. IBM Software Group studies [3, 4] found that it took 72 minutes to migrate a DNS server, and 110 minutes to migrate a DHCP server.

Migrate Domain Controllers A Domain is an IT environment of computers, network resources, and people that share a common security model. Users in a Domain are authenticated via passwords, and resources are protected according to authorization. The main characteristics of a Domain are:

• Central username/password management • Supports logon scripts • Supports roaming profiles

Windows NT Domains A Windows NT Domain is implemented by setting up a Windows NT server as a Primary Domain Controller (PDC). One or more backup Domain Controllers could be used for fault tolerance. The PDC maintains the domain control database in a Windows registry known as the Security Account Manager (SAM). Thus, the PDC plays a key part in domain user authentication and in synchronization of the domain authentication database with Backup Domain Controllers.

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In addition to file/print serving, SAMBA is also a viable replacement for a Windows NT Primary Domain Controller. An IBM Software Group study found that it took 145 minutes to migrate a test Windows Domain to SAMBA running on Linux. Most of the migration time was spent in making sure the configuration files reflected the right information.

Windows 2000 and 2003 Domains Microsoft introduced Active Directory when it released Windows 2000. Windows 2000 and 2003 Domains are comprised of Domain Controllers. A Windows 2000 or a 2003 server can function as a Domain Controller when Active Directory is installed/enabled on it (Windows 2003 comes bundled with Active Directory). Active Directory can be considered a combination of a Directory Service and Network Resource Access control. While the primary function of Active Directory is to serve as a Directory server, it is very complex and can be thought of as containing LDAP, Kerberos, DHCP, and other protocols (with proprietary extensions, of course). This makes Active Directory deployments complex, with customers having to restructure their network infrastructure (DNS, etc.) in conjunction with an Active Directory roll-out. Deployment of Active Directory increases customers’ reliance on the Microsoft platform. It is a widely held view that Microsoft uses proprietary technology and product dependencies to lock users into the Windows platform. For example, said Robert Francis Group: "Microsoft has historically and continues to use its Embrace and Extend strategy to increase customer lock-in on its platform." [6] Likewise, said Gartner Group:

In discussions with its clients, Gartner has found that many enterprises and governments worldwide are actively looking for alternatives to Microsoft. The reasons for this attitude are varied. For many IS departments, the desire for alternatives is because of the controlling influence Microsoft has over their companies' IT strategies (most notably driven by at least the perception of price increases, led by Microsoft's Licensing 6.0 and the desire to increase flexibility by decreasing dependence on any one vendor).[7]

Let’s consider one such case. Use of Active Directory creates an imperative for Active Directory/Application Mode to leverage Active Directory skills and to reduce training and support costs. Active Directory/Application Mode requires Microsoft Identity Integration Server ® (MIIS) to interoperate with Active Directory. MIIS in turn is dependent on SQL Server. This sequence has led many customers to look for flexibility in upgrades and vendor choice. While SAMBA can interoperate in an Active Directory domain as a member it is not very effective as a replacement for the Domain Controller. IBM Software Group study found that a stack comprising of XAD (from PADL [8]) + LDAP + Kerberos 5.0 running on Linux would serve as a viable alternative for Active Directory-based Windows 200x domains. The time required to migrate a test Windows 2000 Active Directory-based domain to the aforementioned stack was found to be about 140 minutes.

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Migrate Mail Servers Microsoft eliminated mainstream support for Exchange 5.5 at the end of 2004. It has announced that mainstream support for Exchange 2000 will be withdrawn by the end of 2005. Customers looking to stay with the Microsoft platform would have to go through a series of upgrades to the products listed below to maintain their collaboration suites:

• Exchange 2003 • Windows Server 2003 • Active Directory • SharePoint ® Services • SharePoint Portal Server

It is easy to see that the upgrade path can be expensive and would also involve a hard to remove commitment to the proprietary Microsoft platform. Thus, customers are looking for an alternative to Exchange. Many Exchange customers faced with this problem have migrated to Domino running on Linux to get the following benefits: [9]

• Reliability and security • Lower total cost of ownership • Integrated business-grade instant messaging (IM) • Off-line support for Web access • Integrated unsolicited bulk e-mail (spam) controls

IBM Software Group has published studies [3, 4] with detailed information on the migration from Exchange (both Exchange 5.5. and Exchange 2000) to Domino. The studies found that it takes about 2.4 person/weeks to migrate 500 Exchange users to Domino. A common concern during the migration is the impact on clients. Following are some possible options:

• Retain the existing Outlook® client and connect to Domino instead of Exchange. • Migrate the Outlook client to a Notes® client. • Enable Web Access for e-mail access using a Web browser. Use a browser plug-

in to access mail offline. This option also paves the way for replacing Windows desktops with Linux.

Administrators use a phased approach for migration from Exchange to Domino in most cases. There is a need for coexistence of both the Exchange and Domino environments during migration to enable unhindered communication between Exchange and Domino users. This coexistence can be enabled by using an Exchange connector for Notes on the Exchange server. IBM and a few third-party vendors provide tools and services for migration. The references [9] provide a detailed overview of these tools and the migration process. Following is a list of tools:

• Domino Upgrade Services (IBM) • Automated Deployment Tool (Wolcott Systems Group®)

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• Common Migration Tool (Binary Tree®)

Migrate Legacy Microsoft Applications Microsoft has announced its intention to discontinue support for legacy application technologies and tools (e.g., Visual Basic® 6.0). Customers using Microsoft application technologies are now considering migrating these applications to open platforms that provide them with the flexibility to upgrade when desired, as well as choice of deployment on different operating systems, including Linux. Many customers are moving to J2EE to run their applications on WebSphere Application Server. The following sections provide an overview of legacy Microsoft technologies and the J2EE application stack to which they can be migrated along with the set of tools that would be helpful in migration.

Legacy Microsoft Application Technologies The Microsoft technologies to be migrated to the WebSphere J2EE platform can be divided into two types: server-based and client-based. Server technologies include:

• Active Server Pages (ASP) • ActiveX Data Objects (ADO) to access data • COM (Component object model) and MTS • SQL Server database

Client technologies include:

• Visual Basic • VB Script • Jscript • HTML Extensions built with Front Page • Windows desktops

Applications using these technologies run on either Internet Information Server (IIS) or natively on the Windows operating System. Microsoft has begun to push the .NET® Framework and Windows Server 2003 operating system as the platform for migration of applications that are based on these technologies. Thus, application developers are now faced with a choice of either moving to .NET or to open standards and Java 2 Enterprise Edition (J2EE). IBM’s WebSphere provides a mature and rich target environment to migrate legacy Microsoft applications, and supports the industry-standard J2EE. .NET, on the other hand, is a relatively new framework and would require a considerable investment and effort on the part of the customer to move legacy Microsoft applications. Robert Frances Group performed a study [10] of both platforms and concluded that WebSphere/J2EE

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was the best choice for enterprise applications. The study also found WebSphere J2EE to be significantly less expensive to operate, especially on Linux. Applications utilizing Microsoft technologies are written in languages such as HTML, Visual Basic, JScripts, Visual C++, etc. An IBM Software Group study [3] found that these applications can be converted to J2EE languages such as Java, JSP, and Java Scripts with the help of certain tools. The table below provides some migration tips based on the study. Migrate From To Using Tool

HTML (with proprietary FrontPage tags)

HTML (based on Open Standards)

Manual or HTML Editors

ASP JSP JASP ® from NetCoole ® [11] ASP2JSP® Converter from DiamondEdge® [12]

Visual Basic ® Script Java Script JASP from NetCoole ASP2JSP Converter from Diamond Edge

Jscript Java Script Manual

Visual Basic® Java VB Converter ® from Diamond Edge

The IBM study also compared manual conversion vs. conversion aided by tools and found that tools can save up to 44% of migration time in certain cases.

Migrate SQL Server to DB2 on Linux Many applications developed using Microsoft technologies use SQL Server as the backend database. Several reasons have forced enterprises to start looking for an alternative to SQL Server, including the following:

• SQL Server CAL’s are no longer included in enterprise licensing (i.e., as part of the Core CAL).

• Microsoft is radically changing the next version of SQL server, called SQL Server 2005 (previously code-named “Yukon”).

• Dependency at the operating system level. IBM’s DB2 database gives customers more flexibility by running on a wide range of server hardware and most of the major operating systems, including Linux. This flexibility has motivated several enterprises to migrate their SQL Server databases to DB2. IBM provides a tool kit [13] for migrating from SQL Server to DB2. The tool kit provides a five-step approach for conversion and even converts stored procedures. An IBM Software Group study [3] found that it took 45 minutes to migrate a SQL Server database containing four tables with several stored procedures and incompatible data types such as BIGINT.

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What If You Cannot Migrate Your Applications Immediately?

Sometimes immediate migration may not be possible, for reasons such as: • Lack of budget. • Time constraints. • Unavailability of skilled people who understand the application.

Fortunately, enterprises can retain their applications but still migrate from Windows to Linux using simulation and bridging techniques while reaping the benefits of Linux. Broadly speaking, simulation techniques fall under two categories: simulation of the native Windows application environment, and simulation of Windows frameworks such as .NET and ASP. Tools such as Visual Mainwin® provide a Windows library to which the application binds and runs native on Linux. The following figure illustrates a Visual C++ application running on a native Linux platform by using the Windows library provided by Visual Mainwin: [14]

Windows frameworks such as .NET and ASP can be simulated within WebSphere/J2EE as illustrated below:

Stryon® [15] provides iASP® and iNET® frameworks for simulation of ASP and .NET frameworks.

IBM Support for Migration to Linux Following is a list of IBM products and services for migration to Linux. Bridging Tools

Simulation of MS Libraries

Linux

C++ Application

Windows Application

Simulated Microsoft Framework

WebSphere J2EE Environment

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• IBM Development tool for Java-COM Bridge and IBM Interface Tool for Java.

• Available on alphaworks www.alphaworks.ibm.com. Migration Station

• Provides migration related information and contains a knowledge base of Linux Papers.

• Visit http://www-106.ibm.com/developerworks/ondemand/migrate/ linux.html#1 for more information.

IBM Pacific Development Center

• Development lab working with IBM Global Services to bring custom software solutions to the world. Activities include migration to Linux.

• Visit http://www.can.ibm.com/pdc for more information. Seminar

• Migrating and Developing New Applications for Linux. • Visit http://www.ibm.com/developerworks/offers/techbriefings/

presentations/linux.html

Summary IBM’s use of Linux provides a good template for other enterprises to employ in their adoption of Linux. The roadmap presented above, in which you begin with your file/print and infrastructure servers and move up the value chain, works best for most enterprises as it lets them reap the benefits of Linux while simultaneously building Linux skills. IBM Software Group Studies [3, 8] provide detailed information on the migration experience from Windows NT and Windows 2000 to Linux. As far as applications are concerned, while it is possible to fully migrate to Linux, enterprises may sometimes be constrained by the lack of budget, skills, etc. In those cases it is easier to adopt Linux as the base operating system using simulation and bridging techniques, and to migrate the application code later. In either case, there is significant value to be gained by eliminating the need for Microsoft Client Access Licenses within your enterprise by deploying Linux.

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References

1. http://www-306.ibm.com/software/success/cssdb.nsf/CS/TKNC-5Q8UYQ?OpenDocument&Site=linuxatibm

2. Linux and ERP: A White Paper by Peerstone Research (ftp://ftp.software.ibm.com/linux/pdfs/PeerstoneLinuxandERP-WhitePaper.pdf)

3. “A Migration Study: Windows 2000 + Active Directory to Linux,” Oct 2004. IBM Software Group. (The URL for this study will be made available here once the study is posted on the web)

4. “A Migration Study: Windows NT4 to Linux,” July 2004. IBM Software Group (http://www-1.ibm.com/servers/ch/downloads/gold/LinuxMigrationV11.pdf)

5. Open Your Windows with SAMBA on Linux, http://www.redbooks.ibm.com/abstracts/redp3780.html?Open

6. Robert Francis Group, “Comparing Windows and Linux Security Head to Head,” March 2004

7. Gartner Group, “Linux and Licensing 6.0 Fuel Ant-Microsoft Movement,” Robin Simpson, David Mitchell Smith, April 24, 2003.

8. PADL – http://www.padl.com (contact sales@padl.com for more information) 9. “Tradeup to Lotus Software” for more migration information

http://www.lotus.com/lotus/offering1.nsf/wdocs/move2lotus 10. WebSphere vs. .NET: Choosing an e-business platform in the enterprise.

Download the report from RFG at : http://www.rfgonline.com/reprints/ibm/RFGJ2EEvsNET.PDF

11. Netcoole - http://www.netcoole.com/ 12. DiamondEdge – http://www.diamondedge.com 13. DB2 Migration Tool Kit - http://www.ibm.com/software/data/db2/migration/mtk/ 14. Mainsoft – http://www.mainsoft.com 15. Stryon – http://www.stryon.com