On Sat, 2019-01-26 at 11:09 -0800, Samuel Sieb wrote: > On 1/25/19 6:45 PM, Jonathan Ryshpan wrote: > > I'm using shred on some 2Tb USB disk drive that I plan to give away. So > > far it has taken 8 hours to shred 50% of the drive, which implies that > > it will take about 16 hours to shred the whole drive. I have another 2 > > drives to go. > > > > Is there a quicker way to protect my data when I give the drives away, > > other than smashing the drives to bits? > > I just checked the numbers and I think you're erasing as fast as you > can. That's a large hard drive and given the write speed of a spinning > disk, that's the time it will take. Can you not write them all at the > same time? I'm pretty sure you're right. Here's what I've found out from a small amount of research and experience. (1) These two things $ dd if=/dev/urandom of=/dev/sdc bs=1M status=progress $ shred -v -n1 /dev/sdc do the same thing, which is to overwrite the drive with random data in a single pass. They both do it at about the same speed, about 40Mbytes/sec., which is probably about the max transfer rate to the drive. Another instance of shred $ shred -v -n1 /dev/sdb applied to an internal drive (which I also plan to dispose of) ran at least twice as fast. Unfortunately I have no actual timings. Another indication that the shredding rate is bounded by the transfer rate. (2) Shred uses less cpu power, as closely as I could judge from a small system monitor on my desktop. (3) Since the time is bounded by the transfer rate, there's no advantage to using /dev/zero instead of /dev/urandom; /dev/urandom is slightly more secure. (4) Repartitioning and reformatting the drive would almost surely be good enough for my purposes; nevertheless it makes me nervous. (5) Bottom line. Repartition and reformat if you think that's good enough; otherwise use shred. Thanks to all - jon _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/users@xxxxxxxxxxxxxxxxxxxxxxx
