Merge GeoWebCache generated tiles from one server with tiles from another server

Question

I have a set of tiles (millions) generated by the builtin GWC in GeoServer 2.1.2 which is stored on server A. I would like to copy all the tiles to server B containing GeoServer 2.1.3 and the corresponding builtin GWC. Server B already contains a completely different set of tiles and we want both tile sets to coexist.

Copying the tile_folder in data_dir/gwc and the workspace seems easy enough, but are there other things we need to consider and is it at all possible to copy generated GWC tiles from one server to another?

I have tried and it doesn't seem to work. So before I dig into the xml configurations, server versions and so on, I would like to know if it is possible at all?

Answer 1

I have never tried merging two tile caches, but I believe a critical piece to get right is the metastore database which is itself stored in the cache directory. The metastore holds key information as cache expiration, disk quotas, etc so my guess is that without those pieces of information GWC will simply not detect the foreign tiles.

One (brute, indeed) approach is to disable this database (see the documentation link above) after having merged the two caches. This will disable some features, but should also force the cache to use that directory structure to retrieve tiles.

A better approach would be to manually merge the two configuration databases, but I have no idea how hard that could be.