In mid April the Microsoft Dynamics division published an interesting internal benchmark: CRM 4.0 deployed on 20 Hyper-V 2008 R2 virtual machines able to serve up to 100,000 concurrent users.
The virtual infrastructure was built on top of two Dell PowerEdge R9100 4U rack servers, each with two Intel Quad-Core Xeon 7560 CPUs.
The first host, featuring 256GB RAM, served 5 virtual machines loaded with SQL Server 2008 R2. The second one, featuring 192GB RAM, served 5 VMs loaded with IIS and 10 VMs loaded with CRM Asynchronous Service.
This system handled 100,000 concurrent users, divided in five organizations, each with four VMs (one web server, two asyncronous servers and one database server).
The users’ activity, generated by the Microsoft Dynamics CRM 4.0 Performance Toolkit, was equal to 5.1M web requests per hour, and 778,000 business transactions per hour. The average response time was 0.29 seconds.
There are a number of interesting details, mostly related to the SQL Server VMs. The Dynamics team had to power each one with 4 vCPUs and 32GB vRAM.
Additionally, it had to use Solid State Drives (SSDs), in a Dell PowerVault MD1220 DAS, to alleviate SQL I/O issues with the large transaction volumes generated during the benchmark.