Hi all. We are in the process of migrating hosts/clusters from old Windows+SQL-based vCenter 5.1 installations to vCenter 6 U2 appliances.
A colleague of mine has expressed concerns about how the PostgreSQL database in the 6.0 U2 appliance will behave given a couple factors. First, let's say we're going to move about 100 hosts running 1000 VMs and perhaps 10 total distributed virtual switches from 1 vCenter 5.1 instance to 1 vCenter 6 U2 appliance. Then, as we upgrade and/or remove old ESXi hosts (we're in the midst of a hardware refresh at the same time these vCenter migrations are going on) and formally 'remove' those old ESXi hosts and associated inventory from vCenter 6/PostgreSQL database, how will the PostgreSQL database 'maintain' or otherwise 'clean itself up'?
The concern he has is probably more along the lines of "I'm familiar with MS SQL far more than the comparatively mysterious PostgreSQL world of new vCenter 6 appliances".
From what I can tell, despite being somewhat 'undocumented' as to its inner-workings and any automated maintenance it has inherently, the PostgreSQL database included in vCenter 6U2 appliances shouldn't have any issues with an admin adding or removing inventory all day long as long as the total number of objects doesn't exceed the sizing of the vCenter appliance itself (Tiny, Small, Medium, Large and their associated maximums). In our case, even though it's probably overkill, we're going to err on the side of caution and size our 2 'largest' vCenters as 'Medium' which is up to 400 hosts / 4000 VMs.
So are my colleague's concerns unfounded? In PostgreSQL 'we trust'? Does anyone have any under-the-hood information about how the PostgreSQL database in 6.0 maintains itself (cleaning, pruning, db consistency checks, and so on)? Thanks.
