A Technical Briefing Paper

Transcription

1 Issue 1 Microsoft Exchange 2000 Migration And Coexistence Strategies A Technical Briefing Paper Introduction 2 From anarchy to consolidation 3 A quick guide to Meta-Directories 8 Conclusion 11

2 Introduction This Paper outlines a pragmatic and effective approach of migration to Microsoft Exchange 2000, which recognises the real-world complexity of diverse messaging systems, and capitalises on the availability of the new generation of tools allowing migration and coexistence. The Paper is aimed at technical managers, architects and consultants who are responsible, or involved in, defining the messaging strategies, deployment and operational services within an enterprise, or an organisation. An assumption is made that the reader is familiar with Microsoft Exchange 2000 architecture, and integration with the Active Directory. 2

3 From anarchy to consolidation Most businesses today are frequently subjected to dynamic forces of mergers, demergers, acquisitions and restructuring within the global market. With this comes the problem of disparate messaging systems that must rapidly be integrated. Most organisations are therefore seeking to consolidate their messaging operation on a suitable technology, which meets their demands for messaging and collaboration services, whilst reducing their Total Cost of Ownership (TCO). The capabilities offered by Exchange 2000, and its close platform integration with Windows and the Active Directory, makes it a very attractive choice for messaging consolidation solutions. Our aim here is to offer businesses and organisations in general, comprehensive strategic paths for Exchange 2000 migration and coexistence. Every organisation is of course different, but we can identify 3 main scenarios: Moving from a homogeneous 1 Exchange messaging system to Exchange Moving from a homogeneous non-exchange messaging system (eg: Lotus cc:mail) to Exchange Moving from a heterogeneous 2 messaging environment (e.g: A mixture of Lotus cc:mail, Notes, Novell GroupWise, and legacy Exchange messaging systems) to Exchange The latter is of course the most complex, but also the most common in enterprise or large multi-national corporations. Our approach is to view the two former homogeneous scenarios as simpler cases of the latter heterogeneous case. As we shall see later, this enables us to offer a single unified strategy that encompasses all scenarios. Exchange-to-Exchange migration requires further special considerations, which are also covered here in this paper. Exchange 2000 migration principles and issues Exchange 2000 migration is commonly misunderstood to be purely the movement of mailbox data from a source messaging system to Exchange In general, the migration process moves (and often transforms) a variety of objects and attributes - users, folders, distribution groups, address lists, mailboxes, messaging connectors, permissions, and similar generically named objects from the organisation s current messaging system(s) into Active Directory and the Exchange 2000 messaging environment. The following is a list of Exchange 2000 migration objects and attributes: User identity information. All groups and group memberships. All attributes related to the messaging environment, such as Internet and proxy addresses, fax number, distribution list membership information, etc. All relevant messaging resources, e.g. mailbox contents, calendar/schedule/organiser, shared folders and message relay connectors. All user security and permissions on messaging resources. All client-related messaging profiles (e.g: Personal Address Books, Personal Distribution Lists, Contacts, Personal Archives). Migration of the above requires careful planning, and there are a number of technical and tactical issues to consider. 1 A homogenous messaging system refers to a messaging environment with messaging servers, which are of the same type, and are supported by a single directory service. For example, all servers run Exchange A heterogeneous messaging environment refers to composite disparate messaging systems. 3

4 What is coexistence and why is it important? Clearly, in all but the smallest organisations, with the best planning and preparation in the world, migration is not going to happen over a weekend. For many reasons - financial, organisational, political and technical - most migrations require a phased approach, lasting weeks, months (and in some cases ongoing or permanent) during which the source messaging systems and the target Exchange 2000 messaging system will coexist. Coexistence therefore spans all phases of migration, and refers to interworkings, the most important of which are messaging and directory synchronisation between all messaging systems and including the target Exchange 2000 solution. Once the last migration phase is complete, the relevant source system(s) may be decommissioned. Decommissioning source systems in turn requires detailed planning to ensure that there are no further dependencies upon these systems, so that no problems are inadvertently left behind. What is Exchange Managed Service and how does it fit in as a strategy? Migration and coexistence presents great challenges and therefore one approach for most organisations would be to hand this problem entirely to a third-party Exchange 2000 service provider, such as Fujitsu. The provider hosts the Exchange 2000 service and is also responsible for moving the existing customer load (mailboxes etc.) over to the Exchange 2000 environment. Fujitsu refers to this as Exchange Managed Service. In a nutshell, Exchange Managed (Hosted) Service is a commercial or marketing solution, which is reliant upon the technical strategies presented here. Exchange Managed Service is outside the scope of this paper. For details of this offering, refer to Fujitsu s White Paper titled Exchange Managed Service - A Low Risk Migration Path to Microsoft Exchange 2000 (Ref: 1034) Technical strategies for Exchange 2000 heterogeneous migration and coexistence We have developed a strategic approach to Exchange 2000 migration and coexistence, which addresses the key requirements of minimum user impact and maximum efficiency, for a range of scenarios and including those stated earlier. The goal is to enable large organisations to establish coexistence quickly, and maintain it for as long as required. Of course, coexistence with particular messaging systems may be permanent due to: Lack of appropriate migration tools. Protection of investment in well developed, well liked legacy messaging applications, which may provide benefits above and beyond those offered by Exchange

5 A Migration Solution is defined as the combination of tools and techniques for moving to the target Exchange 2000 system, from a scenario involving homogeneous or heterogeneous source(s). The solutions can be categorised as follows: Figure 1: The possible strategies between source categories and migration solutions. source(s) migration solutions Point-to-Point - These are solutions based on direct migration and coexistence links (e.g: directory, messaging, scheduling etc.) between the source messaging system, and Exchange 2000 and Active Directory. These links are provided either natively by Exchange 2000 utilities, or else by third-party product vendors. (See Figure 2 for details.) Generic (Meta-Directory) - These are Meta-Directory based solutions whereby the migration of messaging related directory objects from all source systems, occur via a Meta-Directory, over to Active Directory, but messaging coexistence remains Point-to-Point. (See Figure 3 for details.) Non-overlapping Overlapping Point-to-Point Generic (Meta-Directory) Preferred (most common) strategy Least favoured (uncommon) strategy The method for selecting a migration solution is referred to as the Migration Strategy. The strategies presented here are directly determined by the state of the Directory Service(s) of the source messaging systems, and are independent of the specific messaging system implementations and scenarios. The state of the source Directory Service(s) infrastructure is categorised as follows: Non-overlapping - Directory source(s) contain users, and in general containers or structures that do not overlap and can therefore be migrated independently. This applies to homogenous and heterogeneous migration scenarios. Overlapping - Directory sources contain overlapping user accounts and/or structures that can become inconsistent because of the lack of synchronisation between these sources, and therefore require rationalisation or convergence, as they migrate across to the target Exchange 2000 messaging system. This applies only to the heterogeneous migration scenario. At the very minimum, all strategic solutions must establish and maintain uni-directional or bi-directional coexistence links between Messaging Directory databases in each migration source messaging system, and the target Active Directory and Exchange 2000 messaging environment. Meanwhile, the routing topology and messaging connectors must be set up, between source messaging system(s) and the target Exchange 2000, for the duration of coexistence. Solutions must also support migration of mailboxes and the associated user and group access rights (permission attributes) to these objects, from each source messaging system, over to Exchange 2000 and Active Directory. For example, migration from Novell GroupWise & NDS requires translation of the NDS to Windows security on all mailboxes when they migrate. Other messaging resources and their corresponding security attributes may be considered (e.g: shared folders), if tools are available for their migration from source origins. 5

6 Coexistence may cover calendar and client scheduling, using Point-to-Point connectors. For example, Exchange 2000 provides calendar connectors that operate with various versions of Lotus Notes and GroupWise messaging systems, but are limited as they do not cover sharing free/busy information between non-exchange 2000 users. Figure 2: A conceptual representation of an example Point-to-Point solution. Point-to-Point solutions are primarily aimed at the following scenarios: 1. Migration from a single (homogenous) source. 2. Migration sources are non-overlapping. 3. No directory master role exists and Active Directory is chosen as the master (NB - Directory master generally refers to the directory that holds the definitive data and controls the propagation and synchronisation of this information to other directories.) Exchange 5.5 db Netware & NDS Exchange 5.5 GroupWise MCIS Membership SQL db Active Directory MCIS Diagram Keys User and messaging directory Messaging System HP OpenMail db Notes db ronisation Connectors HP OpenMail Lotus Notes 6

7 In this example, the directory system for each source messaging system, i.e. Lotus Notes, MCIS, HP OpenMail, and so on are attached directly, via LDAP or other directory protocols, to Active Directory. These point-to-point connectors control the flow of directory synchronisation messages between individual systems and the target Active Directory, and are often scheduled to run at specified intervals. Figure 3: A conceptual representation of an example Generic solution. The message routing is also point-to-point, between Exchange 2000 and the individual source messaging systems, and is often based on SMTP links. This is to avoid the storage of multiple addressing formats, complexity and overheads of address translations associated with messaging connector gateways. Generic (Meta-Directory) solutions are more appropriate in the following cases: 1. Migration sources are overlapping. 2. A directory master already exists and Active Directory is to synchronise with it. 3. No directory master role exists and the Meta-Directory NOT the Active Directory is to become the master. In this case all messaging directories, including Active Netware & NDS Meta-Directory Directory, are synchronised with a Meta-Directory. The message routing is no different to the GroupWise previous example, and is point-to-point, between Exchange 2000 and the individual source messaging systems. Exchange 5.5 db Active Directory Exchange 5.5 Exchange 2000 Diagram Keys User and messaging directory Messaging System HP Open Mail db Notes db ronisation Connectors HP Open Mail Lotus Notes Meta-Directory 7

8 A quick guide to Meta-Directories Meta-Directories provide integrity, propagation and/or synchronisation of shared data for disparate applications, databases and directories, across the enterprise. The most widely used Meta-Directory products in the market are: iplanet Meta-Directory - a component of the iplanet Unified User Management Suite. iplanet Meta-Directory extends the integration capabilities of Netscape Directory Server, and is a powerful strategic tool adopted by Netscape and Sun Microsystems. CP Meta-Directory Server from Critical Path. CA e-trust - An interesting feature of this product is it s claim to be fully X. 500 compliant. Novell edirectory - The latest release of the Novell NDS product. Microsoft Meta-Directory Services (MMS). In terms of architecture, Meta-Directories contain a set of connectors for information exchange between the Meta-Directory and various data stores or directories, in a hub and spoke topology as depicted in Figure 3. Taking the CP Meta-Directory Server as an example: 1. Universal Database Connector - Uses LDAP and SQL protocols, and provides access to databases across the enterprise. 2. Network Operating System Connectors - Provide access to network operating systems across the enterprise, with the ability to update operating system user accounts and/or network equipment based on changes made in other databases. 3. Application Connectors - Link applications to other databases and applications, and ensure that only authorised users have access. 4. Universal Connector - Enables end users and third parties to build connectors to applications not directly supported by Meta-Directory, increasing the value of all applications in an organisation. The main issue with the Meta-Directory solution is the provision of shared data. This is typically achieved by using the most comprehensive source of data available for creating the Meta-Directory objects, and subsequently merging corresponding objects from other sources. Various data sources may be used, for example messaging directories, Human Resources database, or even flat files accessed via customised scripts. In heterogeneous migration, Meta-Directory and Point-to- Point tools can be used in hybrid. If Point-to-Point tools for migration from particular messaging systems to Exchange 2000 and Windows Active Directory were available and exceed the level of functionality offered by the relevant Meta-Directory connector, then it would be more appropriate to use these to populate the Active Directory. Subsequently, the Meta-Directory s Active Directory connector can reflect these migrated objects in Meta-Directory, by creating new objects, or merging data into an existing object hierarchy. An example of this hybrid approach is the use of NetiQ NWM Netware/NDS migration tool in conjunction with MMS. NWM migrates user and permission objects into Active Directory. Active Directory can subsequently create the MMS Meta-Verse objects directly, using the MMS Active Directory Management Agent. 8

9 Exchange-to-Exchange 2000 migration and coexistence As stated at the beginning of this Paper, Exchange-to- Exchange 2000 migration requires special consideration. Within the framework of migration from Exchange systems to Exchange 2000, two strategies can be identified. These are as follows: Exchange Upgrade - Where the existing Exchange organisation is retained and Exchange 2000 servers join the organisation. This is applicable to legacy Exchange systems (e.g: 5.5 or less) in cases where existing Exchange site structures are deemed suitable for Exchange 2000 operations and services. Exchange upgrade strategy is depicted in the following diagram: Exchange Migration - This applies to either legacy Exchange or existing Exchange 2000 messaging systems, where current Exchange organisational structures are unsuitable and major restructuring will be required. Therefore, a new Exchange 2000 organisation will be created and the migration is commonly referred to as inter-org. Examples of relevant scenarios are mergers and acquisitions in existing Exchange 2000 based organisations, and site redundancy and or consolidation in legacy Exchange systems (i.e. 5.5 or less). Exchange Migration strategy is depicted in the diagram on page 10: Mixed-Mode Exchange 5.5 / 2000 Organisation EX2K EX2K Mixed Exchange Site 1 Exchange Data Migration Mixed Exchange Site 2 Exchange Data Migration EX55 EX55 Directory Synchronisation Directory Synchronisation Domain Controller UserX UserY UserZ Domain Migration Windows NT4 Domain UserX UserY UserZ 9

10 Each of the two strategies can be further refined in terms of goals and objectives of the migration process, which in turn influences the order and precedence of the migration activities relevant to the scenario. For example, if the main goal of migration is the quick adoption of Exchange 2000, then the migration of mailboxes can take priority over domain migration. The following is a list of subordinate Exchange migration and upgrade strategies: Strategic migration of accounts into the target Active Directory in small batches - users, groups, and so on - continuing into the future after Exchange 2000 deployment. Messaging objects and attributes - references to mailboxes, distribution lists, public folders and so on - and their contents are migrated independently, in a window between account migrations. Strategic migration of all user accounts, prior to Exchange 2000 deployment. This is followed by migration of messaging objects, as in the previous case. Tactical migration of all user accounts into Active Directory is performed implicitly or otherwise, as part of the messaging objects migration, e.g: NT 4. 0 domains are still used for logons, authentications and accessing resources. Both Exchange upgrade and migration strategies have suffered from a common problem in the lack of an integrated tool set, until recently, with the advent of the Exchange Migrator addition to the existing NetiQ Migration Suite, and the Controlled Migration Suite the new offering from aelita software. New software tools including Meta-Directories and Point- EXCHANGE 2000 ORGANISATION EX2K EX2K EXCHANGE 2000 Rolling Group 1 EXCHANGE 2000 Rolling Group 2 Exchange Data Migration Exchange Data Migration EXCHANGE 5.5 Organisation EX55 EX55 Directory Migration EXCHANGE 5.5 SITE 1 EXCHANGE 5.5 SITE 2 Directory Migration Domain Contoller UserX UserY UserZ Domain Migration WINDOWS NT4 DOMAIN UserX UserY UserZ 10

11 Conclusion to-point tools, from companies such as NetiQ and aelita, enable a range of migration strategies. These reflect the real-world needs of today s organic and often untidy messaging infrastructures. Whatever their starting point, organisations moving to Exchange 2000 can now be confident that the migration process can be shaped to suit their needs, rather than constraining them to artificial timescales. They should also understand that, far from being in limbo, the coexistence space is one they can choose to occupy comfortably, even long-term. Fujitsu provides services that can define a company s migration strategy, design a migration solution and deploy the solution with minimal disruption to the business. Since customer scenarios are different, Fujitsu operates a migration laboratory, where specific customer configurations can be simulated, and migration techniques tested prior to live deployment. Author s profile Dr. Houtan Houshmand is a Doctor of Philosophy in computer network modeling, and senior computer systems designer-consultant with 16 years experience in research, design, implementation and integration of enterprise and mid-range information technology systems. Currently responsible for the development of technical strategies, and service capabilities for Microsoft Exchange 2000 migration and coexistence solutions in Fujitsu Services. Within the chosen strategy, the degree of transparency from the end user s point of view is still in direct relationship to the degree of attention to technical detail, cost and complexity on the part of the migration team. Fujitsu has built up a body of expertise on migration projects, which is available to organisations moving to Exchange Fujitsu s infracare services are branded Infracare. Infracare provides a consistent and integrated set of infrastructure services that deliver locally tailored solutions backed by Fujitsu s global capability. 11

12 Microsoft, Outlook, Windows and Windows NT are registered trademarks of Microsoft Corporation in the USA and/or other countries. Lotus Notes is a registered trademark of Lotus Development Corporation and/or IBM Corporation. InfraCare is a registered trademark of Fujitsu Services Limited in the United Kingdom and other countries. IPlanet Meta-Directory is a trademark of Sun Microsystems, Inc. in the United States and other countries. CP Meta-Directory Server Critical Path, CP and the Critical Path logo are trademarks of Critical Path, Inc. CA e-trust is a trademark of Computer Associates International, Inc. Novell edirectory is a trademark of Novell, Inc, in the USA and/or other countries. Microsoft Meta-Directory Services is a trademark of Microsoft Corporation in the USA and/or other countries. Controlled Migration Suite is a trademark of Aelita Software Corp. NetiQ Migration Suite is a trademark of NetiQ Corporation in the United States and other jurisdictions. Exchange Migrator is a trademark of NetiQ Corporation in the United States and other jurisdictions. FUJITSU SERVICES Observatory House, Windsor Road, Slough, Berks SL1 2EY Telephone: +44 (0) Facsimile: +44 (0) askfujitsu@services.fujitsu.com Web: services.fujitsu.com Fujitsu Services endeavours to ensure that the information in this document is correct and fairly stated, but does not accept liability for any errors or omissions. Copyright Fujitsu Services Limited 2002 Printed in England 05/02 Ref: 1035