I have been away for a few days and just created this new chart. It does not look good.
Note that times are in CEST (UTC +2)
I fully agree with improving the caching. Unfortunately I am not much of a programmer so I would hesitate to contribute to the F-droid sources, but I have some experience managing Linux (fedora) servers. Perhaps I can contribute with the caching stuff and read up on CDN.
Some thoughts about that:
- I dont think we need geographically distributed caches at this point, but we do need enough capacity. Currently the delays are mostly in the servers, not much in the transit over the internet.
- Cache-Control: immutable can be implemented for static content without changing anything else.
When a client supporting immutable sees this attribute it should assume that the resource, if unexpired, is unchanged on the server and therefore should not send a conditional revalidation for it (e.g. If-None-Match or If-Modified-Since) to check for updates.
Current configuration for the favicon is “Cache-Control: max-age=43200, public”, that is 12 hours expiration time. To get started, we could bump the expiration to 24h and apply ‘immutable’ only to images. Getting an outdated image would be relatively harmless I suppose. Something like
<filesMatch ".(png|jpg)$"> Header set Cache-Control "public, max-age=86400, immutable" </filesMatch>
Then monitor the effect on the servers. Later we could add other types like css, js and eventually the actual apk downloads. - The Hetzner VPS may be very resource limited, they are cheap and you get what you pay for I suppose. Unless someone provides the cash for a more powerful solution, we can only get more performance with careful tuning. I could get a VPS and see what I can do if you think that is a good idea.