Hi there.
I'll try and be to the point as I can. I undertook an upgrade from SCOM 2012 SP1 to R2, this was successful. However after a few days had past, I noticed that the log file for the DW DB was growing rapidly, to the point where we hit a real issue. The drive was a comfortable 50GB drive, but in the end had to be increased to just short of 500GB !! Long story short, I wasn't allowed to get a consultant in to help diagnose the issue, therefore, I was consulting Google, Technet articles etc.
The end decision was to DELETE the Data Warehouse DB & log file and create them again from scratch. I've done this, and used the following instructions on how to do so (http://www.3packetsofcrisps.com/2014/04/reset-scom-2012-data-warehouse-database.html). I have data going into the DW DB, or rather did up until midnight, so had around 3.5 hrs worth.
After checking the Operations Manager event log on one of the Management Servers, I can see numerous errors, these include:2115, 4506 and occasionally 8000.
The event 4506 states: "Data was dropped due to too much outstanding data in rule "Rule Name" running for instance "instance name" with id "ID name" in management group "xxx".
After some consulting Google, I read that this might be expected because a lot of data is trying to be written to the DW DB, however, that doesn't explain why it was writing and for some reason randomly stopped.
A quick summary of our environment:
2x Management Servers running Win 2012 Std x64
1x Operations Database server running Win 2012 Std x64 & SQL Server 2012 Std x64
1x Data Warehosue DB server running Win 2012 Std x64 & SQL Server 2012 Std x64
I've checked account permissions using http://technet.microsoft.com/en-gb/library/hh457003.aspx
If you need any more information, please say, I've tried to keep the post as small as possible.
Dave.