VMworld 2016: vCenter Performance

Session: INF8108

Teaser: 5.5 to 6.0 is 300% faster for vCenter operations From 6.0 to 6.5(?) is another 100% higher.

HTML5 vs. Flex client: Shows a chart with dramatically faster HtML5 performance over Flash client.

VCSA vs. windows – When you have a datacenter with heavy load the VCSA far out performs Windows vCenter.

Why move to multiple vCenters?

  • Concurrency
  • Business separation?
  • Geography
  • VDI vs. server workloads
  • Large inventory
  • If VC is 70% CPU or memory, split it

Future: External load balancer will be built-in when using multiple vCenter servers. No more external load balancer needed.


  • When? If latency is 40ms or greater between sites.

PSC Performance Considerations

  • Default size of 2 vCPU and 4GB is sufficient for a majority of customers

vCenter Server Performance Considerations

  • vCenter can accept 2000 concurrent sessions – hard limit
  • VPXD can handle 640 tasks before they get queued – another hard limit
  • Per-host and per-datastore limits: A host can perform up to 8 provisioning operations at once.
  • A datastore can perform up to 128 vMotions at once
  • A datastore can perform up to 8 storage vMotions at once
  • A 10Gb NIC allows a host to do 2x more vMotions than a 1Gb NIC
  • Latency between vCenter and hosts (ROBO) is not a huge issue.
  • Latency between vCenter and the database can impact performance (>10ms)

Impact of Changing Stats level on DB/network traffic

  • Changing between level 1 and level 2, there is a 4x increase in storage/network usage
  • Changing from level 2 to level 3 is another 2x increase

Database Performance

  • Occasional 3-4s query time is fine
  • 10s or more queries are BAD

Is something slow?

  • Check memory/heap size of vSphere-client process on vCenter
  • Memory/CPU of machine running web browser
  • Are plugins functioning?
  • Connection between browser and vCenter
  • vCenter CPU should not exceed 70% on average (spikes are perfectly normal)

If using Windows vCenter, use the SysInternals Process explorer to map Java processes to vCenter services

For VCSA use VIMtop to look at performance

If you increase VCSA memory, heap sizes will automatically be increased upon reboot.


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