I have been looking at using Custom properties on Nodes to set a more suitable "Maintenance Mode" for our servers, as detailed in a few posts on Thwack.
To do this i have created a custom property for nodes, called "Maintenance_mode". To remotely put our servers in to maintenance i simply ran a scrip remotely, directed at the SQL database that changed the value in the Nodes table from 0 to 1. To remove from maintenance, i simply ran the script again and passed a 0.
The issue i noticed is because of the granular permissions which we set on the SQL backend. After the recent upgrade to SAM this functionality stopped working - here is why:
The nodes table which we had granted a service account (used to run the scripts) read and write permissions to was renamed to NodesOLD. This has now been replaced by a View in SQL which we have had to target instead.
This post is meant for information to other users, rather than for assistance. if anyone has issues with this, reply and i will advise where possible!