vCenter Performance Sizing Calculator

[TheVMinator]

I would like to look at the performance demands relative to vCenter Server in various configurations.  For example, the current sizing calculator tells you how much disk space you need based on number of VMs, Number of hosts, and statistics logging level.  However, it doesn't tell you how much RAM you need at a given statistics logging level.

How can I estimate the performance demands in terms of RAM created by moving vCenter server to a higher statistics logging level such as from 1 to 2?

[vmMarkA]

When changing stat levels, disk has the largest impact obviously as additional data is now being stored.

Memory is not really impacted by the stat level change as data points are not kept in memory but read/written to disk and recalled when necessary.  So memory is still sized based on inventory and services (see resources below for guidance).

Other great resources:

http://kb.vmware.com/kb/2021202

http://www.vmware.com/files/pdf/techpaper/VMware-vCenter-DBPerfBestPractices.pdf

[TheVMinator]

Thanks for the info. I think the documentation is very clear on helping you estimate the amount of space that you need.  What is less clear are the performance demands for the various statistics levels.  The example gives throughput demands for different statistics levels.  Statistics level 1 tested at 7400 kB per second in the example from the second link you sent. Statistics level to tested at 14,000 kB per second. What was the performance impact measured in Iops?  It doesn't say.  I guess you would have to know what your SQL Server is used to in terms of throughput.  My vCenter server and my SQL server are on different vms. Is throughput on SQL Server the only thing I need to look at?  What about the impact in terms of CPU demands on the SQL Server?  How do I know I'm not going to reach a limit there? I only want to go to statistics level two. However it still does seem difficult to estimate the performance demands. I'm not completely confident about making the change based on the amount of information the VMware provides.  It will be nice to get some other people elsewhere with tested it some other people in the industry who can testify to their experiences.