Downsizing HMC Environment to Prepare for Exchange 2010 SP2 Hosted Solution – Part1 - GD Bloggers - Site Home

As most of Hosted Messaging and Collaboration (HMC) companies start planning to migrate to Exchange 2010 SP2 hosted environment due to the change in strategy that was announced about the future of /hosting mode here, so most HMC customer have to move directly to Exchange 2010 SP2 in hosted mode as discussed here, and one of the activities come up to migrate from HMC to Exchange 2010 SP2 is Downsizing activity in the running HMC environment to utilize part of hardware to be reused in the new Exchange 2010 SP2 environment, and although it looks like a simple activity for some IT people but there are a lot of challenges that can be in some cases for some specific HMC components show stopper to continue the downsizing activity, one of the important resource while working in this activity is Microsoft
Provisioning System SDK that can be downloaded from here.

In this post series I will share all my experience with HMC downsizing activity and explain how I deal with different challenges I found in downsizing HMC.

First step of this activity is to carefully plan for the whole downsizing activity and to chose which HMC components that will be decommissioned from the running HMC solution without affect the whole HMC solution functionality, considering the current load and utilization of each role, below is different selected roles and the reason behind the selection:
- Exchange Edge Servers – consider keeping minimum 2 Exchange Edge Servers for load balancing and keep Exchange Edge high available
- OCS Edge Servers - consider keeping minimum 2 Edge Servers for load balancing and keep OCS Edge high available
- TMG Servers - consider keeping minimum 2 TMG Servers for load balancing and keep TMG high available
- Exchange Hub Servers - consider keeping minimum 2 Exchange Hub Servers for load balancing and keep Exchange Hub high available
- Exchange CAS Servers - consider keeping minimum 2 Exchange CAS Servers for load balancing and keep Exchange CAS high available
- OCS Archive and Monitoring Server – consider that you are going to lost OCS Archiving feature which is optional in HMC environment, if not then you should keep it.
- OCS Front End Servers - consider keeping minimum 2 OCS Front End Servers for load balancing and keep OCS Front End high available
- OCS Web Access Servers - consider keeping minimum 2 OCS Web Access Servers for load balancing and keep OCS Web Access high available
- Provisioning Front End Servers - consider keeping minimum 2 Provisioning Front End Servers for load balancing and keep Provisioning Front End high available
- Active Directory Domain Controllers - consider keeping minimum 2 Domain Controllers for load balancing and keep Directory Service high available
- Exchange Mailbox Servers – Considering keeping minimum 2 Exchange MBX Servers for in Cluster (2 CCR nodes or 2 Active/Passive SCC nodes) and keep Exchange MBX high available, and this is the most critical components in downsizing activity because of Microsoft Provisioning System (MPS) Resource Manager dependencies on Exchange MBX resources.
Second step is the preparation for decommission of each server role, and preparations is something that should be done for each role target for decommission as following:
- Exchange Edge Servers – for Exchange Edge decommissioning you will need to remove edge servers that are target for decommission from Edge Subscription from Exchange Hub as described here, then to delete Edge subscription form each Edge Server that will be decommissioned as described here, this beside the important step to remove the decommissioned Exchange Edge Server from the list of Edge Servers in Load Balancer (Load Balancer may need to be refreshed and disconnect all current sessions) or in External DNS.
- OCS Edge Servers – for OCS Edge decommissioning simply you will need to remove OCS Edge from Load Balancer (Load Balancer may need to be refreshed and disconnect all current sessions), and update OCS configuration from OCS front end by removing the decommissioned OCS Edge Server.
- TMG Servers – for TMG you should take care about removing TMG Servers that are target for decommission from the existing TMG array and to remove the decommissioned TMG Servers from any computers sets and/or access rules.
- Exchange Hub Servers – for Exchange Hub you should consider removing Exchange Hub Server that are target for decommission from Load Balancer (if any Load Balancing configuration done for internal application SMTP relay), and to update all Send and Receive Connectors to not include these Exchange Hub Servers.
- Exchange CAS Servers– for Exchange CAS you should consider removing Exchange CAS Servers that are target for decommission from computer sets in TMG configuration, then to remove it from Load Balancer (Load Balancer may need to be refreshed and disconnect all current sessions), then you need to remove CAS Servers that are target for decommission from Offline Address Book Servers list that were added by “AddOABCAS.xml” [<installdir>:\Program Files\Microsoft Hosting\Provisioning\Samples\Managed Email 2007] from MPS using the following procedure:
  1. Use GetOABCASPoolDefault.xml to get the CAS Pool Name
  
  2. Use Get OABCAS.xml to know which CAS servers are member in CAS Pool for OAB
  
  3. Use DeleteOABCAS.xml to delete CAS that will be decommissioned
  
  And one of the best practices for CAS decommissioning in HMC environment is to shutdown CAS Servers that will be decommissioned for a certain time and check that everything in the HMC environment is working good
- OCS Archive and Monitoring Server – for OCS Archive and/or Monitoring Server all you should take care about is to uncheck the option to Enable Archive and/or Enable monitoring from OCS Front End Server
- OCS Front End Servers – for OCS Front End Servers you need to remove all Front End Servers that are target for decommission from Load Balancer, and update OCS configuration to not include the decommissioned OCS Front End Servers in list of Front End Servers from OCS Front End and from OCS Edge Servers
- OCS Web Access Servers - for OCS Web Access Servers you need to remove all Web Access Servers that are target for decommission from Load Balancer, and to deactivate Web Access Server follow Microsoft Documentation here
- Provisioning Front End Servers – for provisioning front end servers decommissioning, you should consider removing front end servers that are target for decommission from load balancer
- Active Directory Domain Controllers – for Active Directory Domain Controllers it is very important to move FSMO roles from all Domain Controllers that are target for decommission, also to remove these Domain Controllers from list or preferred Domain Controllers in Control Panel (If this was configured in Control Panel)
- Exchange Mailbox Servers - for Exchange Mailbox Servers decommissioning a lot of preparations should be done carefully, this will include steps to update the MPS resource manager before moving or deleting any objects considering Moving Mailboxes using script that should de-allocate Organization assignment from each Mailbox Store then allocate the Organization assignment to the target Mailbox Store then to move the Mailbox to different Mailbox Store I will share the correct script to be used for this critical step, and this will be discussed later in different post of this post series.
Third step is the decommissioning activities itself specially, and this will be discussed later in different post of this post series.
Fourth and last step is the post decommissioning activities, and this will be discussed later in different post of this post series.

In the next post I will continue with the decommissioning preparation activities related to MBX server role and MPS activity related to it, followed by 3rd and 4th steps for downsizing activity, this will be coming soon be tuned.

As a conclusion HMC downsizing activity need some planning and should be done carefully to avoid any risk that can affect the HMC production environment.

Part1: http://blogs.technet.com/b/meamcs/archive/2012/11/11/downsizing-hmc-environment-to-prepare-for-exchange-2010-sp2-hosted-solution-part1.aspx
Part2: http://blogs.technet.com/b/meamcs/archive/2012/11/12/downsizing-hmc-environment-to-prepare-for-exchange-2010-sp2-hosted-solution-part2.aspx

Part3: http://blogs.technet.com/b/meamcs/archive/2012/11/19/downsizing-hmc-environment-to-prepare-for-exchange-2010-sp2-hosted-solution-part3.aspx