JEHolo3 I'm curious about this as well. But have a few additional questions...
We have been running well over that 10/20 vCenters with Usage Meter 3.3.x but the number of hosts and VMs under each is quite a bit lower. We often run into reporting issues which require truncating databases to allow the monthly reports to complete but we also see that in sites with very few vCenters hooked into the Usage Meter so number of vCenters and VMs don't seem to correlate to that problem. However with the new collection method in version3.4/3.5 our current experience isn't necessarily valid anymore. We have been hoping the new collection method would hopeful will resolve the reporting issues we have on a monthly basis regardless of it being a small or large site (based on release note information and advice from VMware Support).
To expand your question I see the following information in the doco:
Reference 1: The 3.5 Beta Release Notes state the following under Known Issues:
vCloud Usage Meter 3.5.0 Release Notes.pdf
‘Virtual Machine History’ Report with large data set may not get generated Usage Meter supports metering up to 20 vCenter Servers that manage up to 20,000 virtual machines. However, when vCenter Servers log high volume of events, after a while 'Virtual Machine History' report may not get generated. Workaround: To be fixed in a future release.
Reference 2: As you noted in the 3.5 User guide it states the following under System Requirements (I believe its not just about the vCenter limit that is the issue here but each of them together, hence adding the extra items):
vCloud Usage Meter 3.5.0 User's Guide.pdf
Capacity Metered
vCloud Usage Meter can meter at least up to:
- 20 vCenter Server instances
- 20,000 virtual machines
- 1,000 customers
For me that raises the following questions:
- Like yourself I'm wondering, does the "at least up to" indicate a soft limit rather than a hard limit?
- Like yourself I'm wondering, what is the impact of going over these limits? (other than the one called out issue around the Virtual Machine History report, which for us isn't )
- Is the limit more related to the vCenters, the VMs, or the customers? (for us generally the number of vCenters are exceeded well before the other limits)
- Or is the limit more a case of the first one that is breached?
- How were these values determined as the limit?
- Will resizing the Usage Meter VMs improve things at all or is there an application limit at play here?
- What does the roadmap look like around expanding the metering limits?
The obvious answer is that we should just follow the Capacity recommendations, but we are already running 9 Usage Meters across 10 sites. Having to use 3,4,5,or even 6 Usage Meters in some of larger sites could/would represent a burdensome overhead that may mean truncating databases each month is more acceptable.
Having said the above, I still believe the Usage Meter and vCAN/VSPP is the best subscription based licensing process around. And like to hold it up to our other vendors as the goal that they should be shooting for.
