I have to sync a 63GB folder containing 1313753 files using rsync to an external hard drive formatted with NTFS.
After a while of syncing with around 5MB/s (which is okay I think) I run into the problem that the file transfer rate goes down to zero (checking with iotop) for a while and after that only goes on with ~20KB/s. If I let it run in this state for some days I get some I/O errors in the rsync output and if I check the filesystem of the hdd on Windows it shows that it is damaged and needs to be repaired.
I tried on different systems and with different new hard drives - it's always the same behavior.
I tried with: CentOS 7 Machine, new external hard drive USB 2.0 connected, mounted with ntfs-3g Fedora 29 Machine, different new external hard drive USB 3.0 connected, mounted with ntfs-3g
If I try to sync this folder to an external hard drive formatted with ext4 it's working like a charme and without any errors.
What could be the reason for this trouble?