We are at 97% utilization now that we've mirrored another Ubuntu repo. These hosts don't grow gradually, but in fits and starts, so I don't think we need to try to model a growth rate, but it will be good to have some spare capacity for the next mirroring operation. Please add a 40G LVM PV to the host and extend the existing VG and LV. The two AWS puppetmasters are down right now doing the same thing, so this isn't a good time to restart the scl3 master - ping me in a few hours or tomorrow to check if it's a good time.
Same for releng-puppet1.srv.releng.scl3.mozilla.com
Given that you're on LVM, I'm thinking about reworking the virtual disks for OCD purposes (shuffling you onto one PV instead of 3 weird ones), and then expanding you. Assuming you're not in crisis, we'll get you worked out here in a little bit.
Resize completed, no reboot needed. 89% on /data on both.
Aren't you awesome! :) Thanks