Virtualization Web/Tech

VMware vCloud Air Database Performance Scalability with SQL Server

Previous posts have shown vSphere can easily handle running Microsoft SQL Server on four-socket servers with large numbers of cores—with vSphere 5.5 on Westmere-EX and more recently with vSphere 6 on Ivy Bridge-EX.  We recently ran similar tests on vCloud Air to measure how these enterprise databases with mission critical performance requirements perform in a cloud environment. The tests show that SQL Server databases scale very well on vCloud Air with a variety of virtual machine (VM) counts and virtual CPU (vCPU) sizes.

The benchmark tests were run with vCloud Air using their Virtual Private Cloud (VPC) subscription-based service.  This is a very compelling hybrid cloud service that allows for an on-premises vSphere infrastructure to be expanded into the public cloud in a secure and scalable way. The underlying host hardware consisted of two 8-core CPUs for a total of 16 physical cores, which meant that the maximum number of vCPUs was 16 (although additional processors were available via Hyper-Threading, they were not utilized).

Windows Server 2012 R2 was the guest OS, and SQL Server 2012 Standard edition was the database engine used for all the VMs.  All databases were placed on an SSD Accelerated storage tier for maximum disk I/O performance.  The test configurations are summarized below:

# VMs, # vCPUs, Memory configurations tested

DVD Store 2.1 (an open-source OLTP database stress tool) was the workload used to stress the VMs.  The first experiment was to scale up the number of 4 vCPU VMs.  The graph below shows that as the number of VMs is increased from 1 to 4, the aggregate performance (measured in orders per minute, or OPM) increases correspondingly:
vCA_SQL_4vCPU
When the size of each VM was doubled from 4 to 8 virtual CPUs, the OPM also approximately doubles for the same number of VMs as shown in the chart below.vCA_SQL_8vCPU

This final chart includes a test run with one large 16 vCPU VM.  As expected, the 16 vCPU performance was similar to the four 4vCPU VMs and eight 2vCPU VM test cases.  The slight drop can be attributed to spanning multiple physical processors and thus multiple NUMA nodes within a single VM.

vCA_SQL_16vCPU

In summary, SQL Server was found to perform and scale extremely well running on vCloud Air with 4, 8, and 16 vCPU VMs.  In the future, look for more benchmarks in the cloud as it continues to evolve!

For more information on vCloud Air, check out these third-party studies from Principled Technologies that compare it to competitive offerings, namely Microsoft Azure and Amazon Web Services (AWS):