16TB Volumes and SNMP On Windows
Solution 1:
A while ago there was a patch for Net-SNMP 5.5 which introduced a new option realStorageUnits
for the configuration file.
From the Redhat Bugreport #748410:
To address this issue [negative hrStorageSite values], this update adds a new option to the /etc/snmp/snmpd.conf configuration file, realStorageUnits. By changing the value of this option to 0, users can now enable recalculating all values in hrStorageTable to ensure that the multiplication of hrStorageSize and hrStorageAllocationUnits always produces an accurate device size.
(text in [brackets] is mine)
So adding the configuration directive realStorageUnits 0
to your snmpd.conf might be solving your problem.
However, the values will not be correct up to the very last megabyte; ymmv.
I can't tell if this patch was included in your binary distribution of Net-SNMP, but it would be great if you could report the results and what binary you are using. Also, I didn't test it for the lack of adequate hardware right now.
Solution 2:
I know this is not a direct answer to your question, but perhaps it will help. I suggest you try contacting the team that makes SNMP Informant: http://www.snmp-informant.com/
They extend the Windows SNMP agent to work around Microsoft's limitations for some of their OIDs. I use it with Zenoss to get more accurate CPU utilization and storage numbers and there is a good chance this will work around your issue, but I can't say for certain.