I’ve been doing some log analysis on requests to the OSMF-hosted standard tile layer on tile.openstreetmap.org. To do this I downloaded two hours worth of logs and loaded them into PostgreSQL to run some queries. The logs start at ###, and total 11GB compressed starting at 1600 UTC on 2021-02-25.

My main concern has been backend server load, so to analyze that I looked at cache misses - requests where the cache has to request a tile from the OSMF-operated backend servers. Typically the number of tiles requested is going to be five to ten times higher than the number of misses, but it will vary by zoom.

Total cache misses were 3437.4 per second.

The top five referers, as well as some interesting ones are

Referer domain	Cache misses per second
None	1254.3
www.openstreetmap.org	418.7
www.openrailwaymap.org	16.0
apps.sentinel-hub.com	15.0
m.turkiye.gov.tr	13.1
localhost, on various ports	30.7
10.* IPs	14.2
Other	1675.4

The top sites vary by time and what parts of the world are awake, but most of the traffic is from the long tail of small sites, OpenStreetMap itself, or an app which should be sending a custom user-agent instead of a website with a referer.

For user-agents, I grouped different versions of some apps together. Like before, I’ve got some of the top ones, then a few interesting ones.

User-Agent	Cache misses per second
MapProxy, all versions	281.8
QGIS, all versions	69.9
Fake FF 84	46.8
Marble, all versions	34.3
ArcGIS Client Using WinInet	32.8
StreetView, all versions	29.6
com.caynax.sportstracker, all versions	24.7
Maperitive, all versions	24.2
JOSM, all versions	22.9
Fake Chrome 25	22.2
Amazon CloudFront	13.5
OruxMaps, all versions	12.4
Fake FF 77	11.7
173A220003203F293A2E3C2A	10.7
cgeo	5.9
Other	597.1

The fake user-agents are in the process of being blocked now.

Like with sites, the long tail is a significant portion of the load. Substantial chunks come from OSM-related apps, FOSS geo-related apps (QGIS, Marble, cgeo), and the biggest source is caching proxies like MapProxy and Amazon CloudFront.

Overall, the usage is

Source	Cache misses per second
OpenStreetMap website	418.7
Caching proxies	295.3
Other geospatial apps	91.3
Fakes	91.4
QGIS	69.9
OSM editing apps	52.5
Internal and testing IPs	44.9
Other websites	1719.5
Other apps	653.9