Hi, We are migrating from Exchange 2003 from a physical server to Exchange 2010 on vmware. I need to spec the requirements for the new VM but i'm not sure if I should be splitting the roles and have a VM for the Mailbox server role and another VM for CAS etc. This seems to be the recommendation on VMs but we are only a small operations of about 100 mailboxes. What is the downside of having one server with all roles providing there are enough resources. Thanks Hi, I suppose that decision is up to you, but anyway. If you do not have an extreme requests for high availability and have lot of resources on your VMware machine, so you can install your exchange as single server with all roles or the second option is install HUB+CAS on the one server and the mailbox role at the second one. FYI - My customer is running Exchange Server with 80 persons, all roles installed on this server. No problem (4x virt. CPU, 10 GB RAM). Forefront included. Petr Weiner

Hi you decision will depend on do you need HIGH availability ? you may want to go for two virtual machines if you want to avoid downtime for activitues like OS patching etc. and make two node DAG. and high availability for CAS and HT can be achieved using a hardware load balencer. CMS Load master is one of cheaper device compared to other vendors Thank you Dhruv

We only have one Exchange server and this will run on a Vmware host. High availability on the Exchange server is not in the agenda as it will be running on the vmware cluster and we can deal with the time it takes to move between nodes. As best practice for a Vm implementation I was wondering if I should split the roles. Thanks for all your replies so far.

As mentioned above. The design is up to you but HA is more for the Exchange. In Exchange 2007, MS did recommend to split the roles but it seems to change with Exchange 2010 as all the roles can be on the same box.

Hi Start with one server and then scale out if it's required, there is no need for separating the roles The only role you need to separate is the Edge role.. Jonas Andersson | Microsoft Community Contributor Award 2011 | MCITP: EMA 2007/2010 | Blog: http://www.testlabs.se/blog | Follow me on twitter: jonand82

Hi, We are migrating from Exchange 2003 from a physical server to Exchange 2010 on vmware. I need to spec the requirements for the new VM but i'm not sure if I should be splitting the roles and have a VM for the Mailbox server role and another VM for CAS etc. This seems to be the recommendation on VMs but we are only a small operations of about 100 mailboxes. What is the downside of having one server with all roles providing there are enough resources. Thanks