Dependancies sudo apt-get install libmicrohttpd-dev libcunit1-dev libcurl4-openssl-dev libapr1-dev libaprutil1-dev basic structure: tracker.c manage: registering tracker connecting to tracker executing request each connection has its own APR memory pool request.c manage calling a pool aware request each request has its own APR memory pool typical connection psudocode: for number or trackers randomly choose 1 get a pooled connection (or create if unavailble) execute a request on the connection if any errors, kill the connection and deallocate it. If its a connection error, mark the tracker as inactive (only if > 1 trackers) if all goes well return the tracker connection to the pool. pool.c manage active/inactive list of trackers. manage a connection pool for each tracker. pool management tasks: every x seconds: check tracker is alive mark tracker active/inactive check number of connections in pools expire oldest connections (LRU) pool is stack based (FIFO) so we can check the bottom of the stack when expiring. file.c Manage the File System Look after pooling File Server connections tracker only calls: get_paths list_keys rename delete file_upload.c Manage directly calling cURL to upload a file. Manage calling Tracker::create.open => FileServer::upload => Tracker::create_close with timeouts and fail over. upload using bytes or FILE file_download.c Manage directly downloading from file server using cURL Manage calling Tracker::get_paths => FileServer::download with timeouts and fail over. Handle callback stream, bytes or FILE return values.