After about 150 days without a reboot a hardware re-configuration made a reboot necessary. Two RAIDs were removed and one was added and now we have 100GB additional space which of course will also be used for the FTP mirror. The two RAIDs were over 7 years old and together they only provided around 230GB. The new RAID is also old hardware but probably only 4 years old and it provides 350GB. In addition to the new hardware there was also a new kernel installed before the reboot.