General Best Practices for deploying Exchange 2010 on VMware vSphere

Best practices do not mean  “A hard and fast rule”, but they are rather some sort of indicators which help you deploy the best possible solution 🙂


  • Start with lesser number of vCPU’s and increase on demand
  • 2vCPU’s minimum for mailbox (ideal 6 vcPUs), Unified messaging and Client Access roles and maximum is 12 cores (vSphere 4 has a maximum limit of 8vCPU)
  • Ensure the total number of vCPU’s is equal to or less than the total number of cores on the ESX/ESXi host machine
  • Performance Counters of Interest to Exchange Administrators are CPU %RDY and %USED


  • 4GB minimum, 10 GB minimum for multiple roles
  • Size it as per workload, if workloads cannot be determined, use the MS Exchange Design best practices
  • No overcommitment, period
  • Reservertion is preferred, but not recommended, may limit vMotion
  • Do not disable the balloon driver (installed with VMware tools)
  • Performance Counters of Interest to Exchange Administrators are Memory %ACTV, SWW/s & SWR/s


  •  Use RDM’s if you need in-guest clustering (no sVmotion)
  •  Install Guest OS on the VMFS datastore
  •  Install Log files and Exchange DB on RDM’s
  •  Maintain a 1:1 mapping between the number of virtual machines and LUNs to avoid any disk I/O contention
  •  Microsoft does not currently support NFS for the Mailbox Server role (clustered or standalone)
  • Performance Counters of Interest to Exchange Administrators are ACTV, DAVG/cmd & KAVG/cmd


  • Allocate Seperate network adapters/networks for VMotion, VMware FT logging traffic & Management traffic
  • VMXNET3 Network Adapter (available if VMware Tools are installed)
  • Do not use paravirtualized SCSI driver when a VM generates less than 2000 IOPS. For more information see VMware KB 1017652. However this issue has been fixed with 4.1 and later
  • Use VST (for VLAN tagging) which is most commonly used
  • Enable Jumbo Frames
  • Performance Counters of Interest to Exchange Administrators are MbRX/s & MbTX/s

General Recommendations:

  • Use smaller VM’s for eg. a mailbox server with 2 vCPU and 8GB RAM (vMotion can be much faster)
  • Size the VM building blocks considering License costs, more VM’s may mean more Licenses
  • During peak utilization ensure mailbox role is designed not to exceed 70% utilization
  • If deploying multiple roles on the server, the mailbox role should be designed not to exceed 35%
  • Typical guidline is to use n+1 HA/DRS clusters
  • Typical ESX/ESXi host can be of 16 cores (4×4 pCore) , 128GB of RAM, 2 HBA’s and 4 Gigabit Network Adapters
  • Run on a DRS cluster for balanced workloads

HA & DRS Solutions

Local site recovery:

  • Either use Vmware HA for VM level failover or use VMware HA+DAG (Database Availability Groups) for VM and Database level failover
  • vMotion, HA and DRS are not supported for MSCS nodes

Remote Site Availability Options:

  • SRM with DAV
  • Third party Software Replication

Backup & Restore Options:

  • Traditional LAN based backups, Agents installed within the Guest OS
  • Use vDR for Other Exchange Serve roles for ex. Client Access or HUB Transport etc
  • Array based backup Solutions

Also, worth visiting the below links:

Microsoft Exchange Server Profile Analyzer

Exchange 2010 Mailbox Server Role Requirements Calculator to calculate processor, memory, and storage

Mailbox Server Storage Design

VMware White papers on Exchange

*The above content is provided with an Assumption that the VMware environment is vSphere 4.x and later

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