The bin/initialdataexport.php script creates XML files that must respect a size limit of 30 MB.

So far, this limit isn't really implemented. The only way is to limit the amount of objects that are exported per file. This isn't sufficient, and may break if the exported content uses large XML text blocks.

The minimum and most immediate action would be to check the size of generated files, and warn that the limit must be reduced if a file is over 30 MB.

The good fix would be to estimate the file size during generation, in a pessimistic way, based on the markup length + content length, and write the file when the limit is reached.