# rm -f /opt/oracle/LAB/datafile/o1_mf_users_d1mb8zg9_.dbf
# /usr/sbin/lsof | grep dbf
oracle 3545 oracle 261uW REG 253,10 524296192 491528 /opt/oracle/LAB/datafile/o1_mf_users_d1mb8zg9_.dbf (deleted)
oracle 3547 oracle 264u REG 253,10 524296192 491528 /opt/oracle/LAB/datafile/o1_mf_users_d1mb8zg9_.dbf (deleted)
oracle 3551 oracle 260u REG 253,10 524296192 491528 /opt/oracle/LAB/datafile/o1_mf_users_d1mb8zg9_.dbf (deleted)
# ls -l /proc/3545/fd/261
lrwx------ 1 oracle oinstall 64 Jan 4 11:16 /proc/3545/fd/261 -> /opt/oracle/LAB/datafile/o1_mf_users_d1mb8zg9_.dbf (deleted)
# dd if=/proc/3545/fd/261 of=/opt/oracle/LAB/datafile/o1_mf_users_d1mb8zg9_.dbf
1024016+0 records in
1024016+0 records out
524296192 bytes (524 MB) copied, 5.49037 seconds, 95.5 MB/s