I am still running 4.0 and don't know if 4.1 is any different, but if you know your syslog device types you could run the lsdata command from the bin directory on the DSRV using totalsbydevice for the statistics switch. Then import the text file into Excel and sort. If anyone knows a better way, I would certainly like to know.
I asked a similar questions here: http://rsaenvision.lithium.com/t5/Tools-and-Scripts/LSDATA-Statistics-Info/m-p/10183 But no answer yet. I'd like to know the storage usage per device, but I don't think the system can do it.
Your lsdata command appears to be correct. 1.5TB of data in a year is certainly possible depending upon your network architecture, the device, and the device's logging parameters. Firewalls and routers may see a lot of traffic and log the activity. Then there's the amount of logs you'll see with Windows 2008 servers unless you scale back what is logged. I've got one W2K8 box that logged over 700GB last month alone. Also keep in mind that the data is highly compressed when it is written to the IPDB. I'm seeing around a 96% compression rate.
The compression is exactly the issue - I'm sure the data amounts are correct, however it would be nice to be able to know how much storage the devices are using, in addition to the volume they've sent.
Try this command: "dir /s C:\ | findstr /b /c:" " >foldertotals.txt". Replace C:\ with the path to your data. It provides the number of files and total bytes for each directory and subdirectory. It's not great but you can work with the text file with a good text editor and import it into a spreadsheet for sorting.