by Mark Jones.
i have been able to backup and restore large courses 800 meg + with these settings.
Warning - once complete change back to your current settings as this does not work well in a production environment. it leaves everything running for a long time and eventually runs out of resources and has to be rebooted.
change this in the php.cfg file
max_execution_time =19200
max_input_time = 1500
max_input_vars = 8000
memory_limit = 1024M
post_max_size = 1200M
upload_max_filesize = 1000M
max_file_uploads = 30
FastCGI Settings
Activity Timeout 3600
idle Timeout 3600
Queue Length 2000
Request Timeout 3600