'Device not configured' error with cp and rsync (NTFS volume on Mac)

Question

I am trying to backup data from one external harddrive to another using cp and/or rsync on a Mac.

The external drives given by diskutil list are:

/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *1.0 TB     disk2
   1:                  Apple_HFS Transcend               1.0 TB     disk2s1

/dev/disk3 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *1.0 TB     disk3
   1:               Windows_NTFS Seagate Backup Plus ... 1.0 TB     disk3s1

They have been mounted on /Volumes/Transcend/ and /Volumes/Seagate respectively.

cp -R ebooks/ /Volumes/Transcend/ebooks/ after running for sometime yields the following errors:

cp: ebooks//中國敦煌學百年文庫: unable to copy extended attributes to /Volumes/Transcend/ebooks/中國敦煌學百年文庫: Device not configured
cp: ebooks//中國敦煌學百年文庫: Device not configured
cp: ebooks//中國明朝檔案總彙: unable to copy extended attributes to /Volumes/Transcend/ebooks/中國明朝檔案總彙: Device not configured

rsync throws up the same error:

$ rsync -r ebooks/ /Volumes/Transcend/ebooks/
rsync: link_stat "ebooks/." failed: Permission denied (13)
rsync error: some files could not be transferred (code 23) at /BuildRoot/Library/Caches/com.apple.xbs/Sources/rsync/rsync-52.200.1/rsync/main.c(996) [sender=2.6.9]

$ sudo rsync -r ebooks/ /Volumes/Transcend/ebooks/
Password:
rsync: link_stat "/Volumes/Seagate/ebooks/." failed: Device not configured (6)
rsync error: some files could not be transferred (code 23) at /BuildRoot/Library/Caches/com.apple.xbs/Sources/rsync/rsync-52.200.1/rsync/main.c(996) [sender=2.6.9]

How else can I complete my backup from here? (It is less than 50% complete.)

---

UPDATE:

Some instances of Device not configured (6) error are apparently caused by the NTFS volume being unmounted halfway through the rsync process.

After running chkdsk on the NTFS volume with a Win7 machine, which fixed some disk errors, I can easily mount the volume using ntfs-3g.

rsyncnonetheless runs into the following error after working for some time:

三編第092冊/000732.pdg": Device not configured (6)
rsync: send_files failed to open "/Volumes/Seagate/ebooks/叢書集成三編/叢書集成三編第092冊/000733.pdg": Device not configured (6)
rsync: send_files failed to open "/Volumes/Seagate/ebooks/叢書集成三編/叢書集成三編第092冊/000734.pdg": Device not configured (6)

I modified my rsync command so that it can continue from where it left off after such disruptions.

rsync -avhP --iconv=utf-8,utf8-MAC --stats --progress --info=progress2 /Volumes/Seagate/ebooks/ /Volumes/Transcend/ebooks

One thing I've noticed is that ntfs-3g automatically unmounts the Seagate volume while rsync is still running, giving rise to the above error.

I've been able to get rsync running again by remounting the Seagate volume with sudo ntfs-3g /dev/disk3s1/ /Volume/Seagate/.

So the next question would be: Why can't ntfs-3g keep the drive mounted until the whole rsync process is complete? Is there a bug somewhere, or did I miss something in my command?