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Re: Speed Problem Copying Files

On Tue, May 14, 2019 at 12:11:17PM -0700, David Christensen wrote:
On 5/14/19 4:23 AM, Michael Stone wrote:
On Thu, May 09, 2019 at 10:48:31PM -0700, David Christensen wrote:
2019-05-09 22:00:27 root@po /mnt/scratch
# time dd if=/dev/urandom of=foo bs=1M count=1K conv=fsync

don't bother doing this, urandom will be the bottleneck and it will just confuse things

That was intended more as a litmus test, rather than a benchmark. I chose /dev/urandom, rather than /dev/zero, to preclude the possibility of caches or compression.

Just use /dev/zero, caching is exactly as relevant to either, and accidently compressing a disk isn't a likely scenario.