I needed to create an Operations Manager server to test something.  I created a virtual machine on my Hyper-V server for this single test.  I just needed Operations Manager installed so that’s why I installed all of the roles on a single server.  After my one test I was going to delete the VM. 

I could not get the Data Warehouse Configuration section of the installer to finish.  Since it would not finish it was rolling back the entire installation.  Frustrated I reviewed the OpsMgrSetupWizard.log file and noticed an error of low memory.  I received warnings during the Operations Manager setup but it was just that, warnings.  If you receive an error during the prerequisite check it won’t allow you to continue but you can continue with warnings.  Since it was a test lab I didn’t want to give the guest a lot of memory since I was going to install Operations Manager and run one test.  Once I increased the memory of the guest from 1GB to 4GB I was able to successfully install Operations Manager.

It’s just sort of strange that the installer uses so much memory causing the install to fail.  Maybe rather than make that a warning about low memory during the prerequisite check it should be an error that won’t allow you to continue. 

Below is the low memory warning.  Notice how it says you need 2GB to install the management server but the installer fails AFTER that point.   

Below is where the install would hang.  Notice how it installs the management Server and fails on the data warehouse even though the prerequisite sais the management server needs 2 GB to install.

Below is the start of the rollback.screenshot.2

It’s rolled back.screenshot.3

Looking at the log files I noticed the error below.
XML document could not be created because server memory is low. Use sp_xml_removedocument to release XML documents.

Once I changed the memory from 1GB to 4GB I didn’t receive any prerequisite warnings.