Noob: I wish to reallocate resources for my guest servers -- still clueless how to measure what's available.

@Brian, not so. I need to increase resources to the non-production, LAB1, to become at least equal to the others -- and without crashing the production VMs as their resources shrink.

Once configured with RHEL 7 and Oracle 12c (and backed up), LAB1 will be loaded with a copy of production data, then used for user-acceptance testing prior to upgrading each production system. Perhaps I should clarify that both RHEL, and Oracle, strongly recommend a clean install of the new product, rather than a migration.

@Andrew, I'll check that out. It's pretty clear, however, that the memory load as a point-in-time doesn't tell me a thing about load over time -- say for a 24x7 week. With a historical record, I might find that PROD2 never goes over 10% CPU.  I could safely pull from that one.

The system log shows that each prod server will throw a resource warning when the daily backup kicks off. I don't need to hear from my tech lead that users called her with after-the-fact complaints :)

@Andrew, thank you. The article is way over my little Pooh head for now, but it will be fun to understand -- eventually. You got me looking for active memory, and this one link caught my eye: https://communities.vmware.com/docs/DOC-10398.pdf.

Think sar or top, piped to a text output.

@Andrew, on current Oracle systems the memory allocation is dynamic up to pre-set limits (targets). Swapping is discouraged -- whereas what I read on this topic, vSphere appears to be just the opposite. I suspect I need to talk to VMware about what one learns in which classes.

However, the answers here have been mostly helpful, thanks. There's one follow-up question about the active memory suggestions. In the pop-up window titled Customize Performance Chart, I figured out to create a custom chart. My earlier frustration was that this tool is locked down to display only the last one hour by default. The last and the from-to controls are not available to me as root. I'd appreciate  any last advice before I have to open a formal service ticket.

@Andrew, thanks -- part of my fog may be that I'm not seeing the same features that you experienced people are -- but I'm coming along.  Also, I had time today to focus in on the CPU/memory/storage consumption. I finally noticed that my time window choices were still locked down, allowing me only the recent-sixty-minutes display. I did experiment with choosing the advanced reporting control. Unfortunately, that didn't seem to unlock my duration radio buttons.

My license is for Essentials, not the plus version, however.

5.10. No to the vCenter, yet. :)

It's the only choice that's presented after O/S login. I read something this week that inferred there's a submenu to provide a limited set of O/S commands, I suspect that's available in some other VM product. Further, whoever set up this master server apparently disabled ssh access.

So, my current action includes a Monday SR with VMware about the apparent locked down options (vClient prohibits changes to the one hour metrics); and to RHEL to work around the command line access. I have a weekend maintenance window coming up, my first opportunity to bounce the master server. And no, acquiring another ESXi host is not likely to happen :(

In the meantime, I've begun manually recording the VMs' consumed resources during the peak hours.

And finally, I feel like my original question has been addressed, how/where to measure the load. I'll create new questions, I'm sure, after the server bounce.  I'll wait for your reply to this, then award points / close.

Regards,
dvz