This command produced the error mentioned above after 9 h (preparing a 2 TB hdd for encryption):
time openssl enc -aes-256-ctr -pass pass:"$(dd if=/dev/urandom \
bs=128 count=1 2>/dev/null | base64)" -nosalt </dev/zero \
| pv -bartpes 1884183960000 | dd bs=512 count=1840023391 of=/dev/sdc3
I got at 50% (9 h) a total written GB count as well as a bs/count information.
Is it possible to resume this process?