[kwlug-disc] block size for dd -- no difference

[William Park]

On 2025-09-03 02:28, Chris Frey wrote:
> On Tue, Sep 02, 2025 at 10:40:54PM -0400, William Park via kwlug-disc wrote:
>> for i in {4,16,64,256}K {1,4,16,64}M; do
>>      echo ==== $i ====
>>      dd if=/dev/sda of=/dev/sdi bs=$i
>>      sync
>> done
>>
>> No difference.  All did 117MB/s.
> 
> Cool test.
> 
> What about CPU load?  What about syscall load?

I didn't look for those.  I just ran it in single user mode with 
read-only filesystem,
     telinit 1
     mount -o remount,ro /
     ...
and went to sleep. :-)