Furthermore, I am observing a steadily increasing number of directories named like pids being created in the root of the cgroup virtual filesystem (mounted at /cgroup). For each connection attempt to a vsftpd daemon a new directory is created. Those directories seem to be never deleted. After a few days of uptime there are about 7,500 directories while there constantly are only about 150 processes running (more or less idling, this server usually has low load).Do they persist if you restart vsftpd?
Yes, all those directories persist if vsftp is restarted. The only way (I am aware of so far) to get rid of those is rebooting the system.
Thanks for your quick response. Dirk