Exchange Server 2000/2003 to Exchange Server 2007: Large Mailboxes Migration/Consolidation

  • Article

This is a case study of a customer who wanted to perform a migration from Exchange Server 2000 / 2003 to Exchange Server 2007 whilst consolidating a number of remote sites to a centralised hub site. The main premise of this engagement was to ascertain Microsoft’s best practice methodologies for migrating very large mailboxes and moving large amounts of data with the least amount of risk of data loss, and the consolidation of globally dispersed messaging environments.

I’d like to send from here a HUGE THANKS to my peer, Ray Khan for putting all of this information together, as he was the one involved on the project and who kindly present to us this awesome case study which hopefully will encourage some other customers!

Problem Statement

This customer had a need to migrate all of their regional site data into a centralised site in UK with the least amount of downtime. They had users with very large mailboxes in China and Japan of up to 40 GB per mailbox, however there were only 30 to 40 users at each of these sites. There was a total of around 600 GB of mailbox data that would be required to be migrated from the regional sites to UK.

The objective was to archive most of the data from these mailboxes onto a new Enterprise Vault platform, so once on Exchange Server 2007 they would only have around two gigabytes of "online" mail.

They had reviewed several migration approaches but wanted our advice on these approaches and any others that have been proven in other environments.

As part of their upgrade project they were also investigating all other messaging platforms including Microsoft’s BPOS solution as well as partner’s and other third party solutions and also considering carrying on running On Premise. This aspect was out scope for this engagement.

Infrastructure before Upgrade

 

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The company has just under a couple of thousand employees. Over 75% of their staff are located in UK and Switzerland the other 25% are located around the major financial centres around the world including China, Japan, and US.

Their Exchange server organization exists inside a single Active Directory Forest running Exchange Server 2003 SP2 in native mode. However there were several Exchange 2000 SP3 mailbox servers situated at some of their key branch offices such as China, Japan, UAE, Canada and Uruguay.

Exchange Estate Summary

  • 31 servers globally, 11 routing groups and 6 administrative groups;
  • they employ a single ended Exchange topology and do not use any front-end servers;
  • 4,128 mailboxes (including resource mailboxes but some are dormant or on disabled accounts);
  • 5.1 TB personal mailbox data and approximately 650 GB of Public Folder data (PF's mostly in UK and Switzerland);
  • The global organisation sends around 850,000 messages a week and receives around 1,000,000 messages a week;

Exchange 2003 Integrations

  • 17 Enterprise Vault 6.x and 7.x archiving servers hosting around 7.5TB of archive data (but not all regions have archiving);
  • 10 Blackberry Enterprise Servers servicing around 800 Blackberry handsets globally;
  • OCS 2007 R1 transitioning to R2;

Many of their users have very large mailboxes, averaging 2 to 4 GB, but in some regions where no archiving exists we have users with up to 40GB mailboxes

Our client estate is based on Windows XP SP3 and Outlook 2003 with SP3 (new workstations with 2GB RAM).

Networks (Global MPLS WAN)

  • 100 Mbps (between UK and Switzerland);
  • 45 Mbps (between UK, China, Japan and US);
  • 2 Mbps (high latency links between UK, UAE, Uruguay, Canada, Singapore, etc.);

Target Architecture

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They planned to transition their entire organization to Exchange Server 2007 SP2 into a consolidated and centralised architecture hosted in our new Global Data Centre in UK. This network will be facilitated by Cisco WAN Accelerators, situated at all of their branch offices.

They were also planning to consolidate and centralise their archiving and BES estate into the UK Global Data Centre.

They were in the planning/design phase of this programme and were scheduled to commence deployment in beginning of 2010 for completion by end of summer of 2010.

Proposed Solution

This customer designed a number of solutions to address the problem statements listed above. They decided to go for the following approach to migrate the Exchange Server 2000 / 2003 users with very large mailboxes and archive their data to the centralised site using SCR data replication technologies... Please refer to the steps below for more detail.

 

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Migration Steps

  1. Install and configure the entire centralised Exchange Server 2007 SP2 infrastructure, EV and BES infrastructure into the Global Data Centre (GDC). Install WAN Accelerators;
  2. Install an Exchange Server 2007 staging mailbox server in the GDC (to receive gross branch office mailboxes);
  3. Install an Exchange Server 2007 MBX/HT as swing server at the remote site (on the same LAN);
  4. Configure staging server in the GDC as an SCR target of the swing box Exchange Server 2007;
  5. Run Move-Mailbox command from Exchange Server 2000 (at the branch office) to Exchange Server 2007 swing box server (move entire existing mailbox over – swing box becomes the production MBX/HT for the branch office users);
  6. Allow SCR to seed the staging server over a period of up to 2 to 3 weeks (however long it is expected to take – after testing) – using SMB 2.0 as both servers will be Windows Server 2008 SP2;
  7. Once all data is migrated across – perform VSS backup of the SCR target – run ESEUtil /G to check database - invoke SCR disaster recovery process and switch the active mailbox node to the staging server in the GDC;
  8. Move BES account to GDC BES server;
  9. Enable EV archiving policy and groom the mailboxes (that are in the staging server) to 1 GB in size – all inside the GDC site (SAN to SAN);
  10. Once complete run Move-Mailbox to migrate the 1 GB mailboxes to the production CCR cluster (SAN to SAN);
  11. Once all data is validated delete the staging server databases used to eliminate white space;
  12. Move Exchange Server 2007 swing box server to the next branch office;
  13. Remove and re-install Exchange MBX/HT in the next branch office site (also rename the swing server);

Summary

This customer decided to migrate to Exchange Server 2007 and to continue managing their infrastructure to On Premise using the above approach. They have managed to migrate their remote site data using the strategy outlined above. They are continuing with us from a support perspective and will be booking further proactive engagements looking forward to migrating to Exchange Server 2010.