On Sat, Jun 22, 2013 at 6:02 PM, Mark Knecht <markkne...@gmail.com> wrote:
> if what you are suggesting is more like this very short example: > > mark@c2RAID6 /VirtualMachines/bonnie $ dd if=/dev/urandom of=urandom1 > bs=4096 count=$[1000*100] > 100000+0 records in > 100000+0 records out > 409600000 bytes (410 MB) copied, 25.8825 s, 15.8 MB/s > mark@c2RAID6 /VirtualMachines/bonnie $ > Duncan, Actually, using your idea of piping things to /dev/null it appears that the random number generator itself is only capable of 15MB/S on my machine. mark@c2RAID6 /VirtualMachines/bonnie $ dd if=/dev/urandom of=/dev/null bs=4096 count=$[1000] 1000+0 records in 1000+0 records out 4096000 bytes (4.1 MB) copied, 0.260608 s, 15.7 MB/s mark@c2RAID6 /VirtualMachines/bonnie $ It doesn't change much based on block size of number of bytes I pipe. If this speed is representative of how well that works then I think I have to use a file. It appears this guy gets similar values: http://www.globallinuxsecurity.pro/quickly-fill-a-disk-with-random-bits-without-dev-urandom/ On the other hand, piping /dev/zero appears to be very fast - basically the speed of the processor I think: mark@c2RAID6 /VirtualMachines/bonnie $ dd if=/dev/zero of=/dev/null bs=4096 count=$[1000] 1000+0 records in 1000+0 records out 4096000 bytes (4.1 MB) copied, 0.000622594 s, 6.6 GB/s mark@c2RAID6 /VirtualMachines/bonnie $ - Mark
