I'm wondering if there's a tool to look into growth of subdir's of a specific volume to see which ones are growing very fast so we can separate them into different volumes ?
Natively you can set null quotas with - for each field but it is per qtree. So if you can use per qtree that would work but might not be the case. The advantage is real time quota report to see usage. And free with tree quotas.
Other utilities are ntp and northern hemisphere which use fpolicy and run externally. And a fee for the software. Both I believe report usage and sizing of individual subdirectories on NetApp.