I've got the exact same problem - tried tweaking NTP for all the different involved resources, with no luck so far. Never opened a TAC case, but I may at some point.
I've got a 6.7 multi-node (primary and DB) install, and for our primary datacenter (which has 23 hosts and about 3000 VMs), each inventory cycle takes around 180 minutes.
That being said, the length of time hasn't caused us any actual issue so far -...
Glad it helped!
There's a been a bug report out there for a while (https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvb75348) so hopefully we eventually get an "official" way to do this in the future.
It's definitely a little frustrating that there's no built in way to do this, but you can accomplish it by creating a very simple Custom Workflow Task.
Go to Orchestration > Custom Workflow Tasks, and create a new custom task (including name, label...
Out of curiosity, what are you trying to do that you don't see a task for in Director? Custom tasks are one option, but the few things I couldn't do, I was able to do either by calling some powershell, generic API calls, or calling into the guest VM ...
