I just ran into a strange issue and haven't seen this documented anywhere so thought I'd post here, as much as an FYI as anything else. We gather data from several hundred filers every night (ranging from 7.3 in 7mode through 8.3 in cmode) for reporting and provisioning purposes. I noticed this moring that I had filers with 2TB volumes in Aggregate that were 0.01TB in size! Needless to say that seemed a odd...
In looking at the results returned from 'aggr-list-info' (this is 7mode) is appears that OnTap 8.0 returns the size parameters in KB, whereas 8.1 and later return it in bytes (7.3 and earlier return an entirly different data structure). I verified this by looking at the output of 'df' against the aggregates in question. According to the official API docs:
fs-size-total =>integer, optional
not settable, online-only] Total size (in bytes) of the referenced file system . If the referenced file system is restricted or offline, a value 0 is returned. Range: [0 - 2^64-1