Disk Requirements

The only support requirement dictated by Microsoft around disk space is that each host must support at least 500 GB of free space. The actual space consumed by Lync virtual machines varies by role and by business requirements for monitoring or archiving data. Using fixed or dynamically expanding disks also has a big effect on how much space is required. Generally, allocating 40 to 50 GB of disk space per virtual machine for the operating system is sufficient. Lync Back-End database Servers or Monitoring and Archiving Servers with a collocated SQL database are going to consume much more space than a Front-End or Edge Server.

Both direct attached storage (DAS) and SAN disks are supported to hold Lync virtual machines. Which option is used depends greatly on the infrastructure that an organization already has in place. SAN provisioning is generally more flexible, but there is a significant upfront cost to these types of systems. DAS storage can be more affordable and yield acceptable performance for virtual machines.

Another consideration for organizations is whether to use a single RAID volume for all virtual machines or to separate each virtual machine disk on to its own physical hard disk. There is no requirement for separate disk spindles, but the best performance is realized if each virtual machine disk can be placed on a dedicated hard disk spindle. The downside to dedicated disks is that unless the disk count is doubled, there is no redundancy at the physical disk level. Many organizations find that placing virtual hard disks on a RAID 1+0 or RAID 5 volume meets the disk requirements of most virtual machines.