On 08/02/2014 12:16 PM, Joel Rees wrote:
As I understand it, he's asking whether any of us on the users list has anaylyzed the output of both /dev/random and /dev/urandom . Not just whether any of us are having issues with blocking, but with the randomness as well.
Another metric is throughput. I recently wanted to fill a 3 TB HDD with random numbers prior to using it with LUKS, so I ran a test on my my Intel DQ67SW i7-2600S machine:
# time dd if=/dev/urandom of=/dev/disk/by-id/ata-ST3000DM001-1CH166_W1F1R3VC bs=4M count=100
100+0 records in
100+0 records out
419430400 bytes (419 MB) copied, 29.2232 s, 14.4 MB/s
real 0m29.225s
user 0m0.000s
sys 0m27.922s
This is more than an order of magnitude slower than the drive's
sequential write throughput.
I would be curious to see metrics for processors with hardware PRNG (e.g. Intel's "SecureKey").
David