I have large raster datasets on AWS S3 (~100gb each) that I would like to serve as WMS through Geoserver.

Has the "S3 Support for GeoTiff" extension been replaced by the "COG" one?

I understand that I would need to process the tiff to be a COG using gdal or rio-cogeo.

2 Answers 2


No, both extensions continue to exist. COG is probably faster (and cheaper) that the general S3 but may require you to reprocess your tiffs to make them COGs.

Just to note that as they are community extensions they aren't really supported in the sense that other extensions are. But users that depend on them could step up to provide support or cash to buy support.


As Ian said, both still exist.

The general S3 one has seen no development in the last few years, while the COG one is being improved regularly. However, the old one still has a few advantages for specific cases:

  • It can deal with any TIFF, not just COGs
  • It works using a local cache, so if the block of data needed is cached locally, it's going to be faster than the COG one, which instead reads from S3 every time needed.

The downside of the old reader is that it basically reads data in 5MB blocks from S3 and caches it locally, so remote reads are always large, and the local cache can grow to be pretty big. Works best for smaller GeoTIFF files, not sure about using it with very large ones, the cache might prove to be ineffective.

The COG reader, on the other hand, reads only the bits it needs, but caches nothing (for the moment, devs are looking for funding to implement an optional caching mechanism).

  • Thanks Andrea, very helpful
    – staf
    Commented Oct 16, 2022 at 23:18

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