On a fresh install of Ubuntu Core 16 (on rpi3) - with no additional snaps, is there any information available which could help me calculate the average monthly data required to keep these 3 (core,kernel and gadget) snaps up to date?
I am hoping to get information on how often these snaps are published by Canonical, and whether these updates are delivered as delta updates? And if so, how big would an average delta update be as a percentage of the total snap size?
As it happens, we’re close to publishing a document which will contain the exact information you’re asking for. In the meanwhile, though, I can provide some general numbers.
Deltas are generated automatically whenever a snap is released, so “these updates are delivered as delta updates” is true in the vast majority of cases, particularly if your device is always connected and is current - deltas are most efficient when they model an upgrade from the immediately previous version.
Core and kernel snaps see between 1 and 3 releases a month. On average deltas are about 30-40% of the size of a full download (this is highly variable but this average covers kernel, core and gadget snap delta sizes).
You can check the size of a full download for the snaps that interest you and estimate the delta size based on these numbers, and with the (admittedly quite variable) average of releases/month come up with an approximation of the data you need.
I’ll be sure to let you know when we publish the document I mentioned.