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On a server running ProFTPd in certain configurations you can see a very slow load time (up to a minute or more) while listing the directory contents. This can be sped up greatly by adding these commands to the bottom of your ProFTPd configuration file. This is generally located in /etc/proftpd.conf:
ListOptions "" maxdepth 3
ListOptions "" maxdirs 10
ListOptions "" maxfiles 1000
Save the conf file and restart ProFTPd.