space reporting on AFF's with compression?

Hello All,

We're migrating from a FAS to a new AFF that has inline compression and 
a guarantee of 3X compression.

I'm trying to convert a graphite/snmp graphing system that reports our 
overall aggregate space usage to the new system.

A straightforward graph of used and free space on the data 
aggregates/tiers shows the right portion of space used but seems to be 
reporting pre-compression usage (and we appear to be getting less than 3X).

The System Manager webUI says we're getting ~120:1 "Data Reduction" but 
it also says we're using 1.74PB and have 14TB available. In fact we 
currently have 48 x 900GB SSDs in two disk groups/tiers and about 40TB 
of actual unstructured data.

Is there a doc somewhere on understanding space reporting with the new 
system including meaningful reporting of compression returns?


Grateful for any help,

Randy in Seattle