Matteo Croce <[email protected]> writes: > Anyway, doing IO operations on Linux bigger than MAX_RW_COUNT will > almost always do a short read/write. > This is noticeable with 'dd' without the option iflag=fullblock: > > $ dd if=/dev/zero bs=1G count=2 |sha1sum > 2+0 records in > 2+0 records out > 2147483648 bytes (2,1 GB, 2,0 GiB) copied, 1,53035 s, 1,4 GB/s > 91d50642dd930e9542c39d36f0516d45f4e1af0d - > > $ dd if=/dev/zero bs=2G count=1 |sha1sum > 0+1 records in > 0+1 records out > 2147467264 bytes (2,1 GB, 2,0 GiB) copied, 1,60673 s, 1,3 GB/s > c4611e872c5a80623c67d39c6a5888c481565045 -
Good point. I was looking at some old bugs yesterday and there is one for adding a warning about this [1]. I agree that it isn't obvious behavior, but sadly I don't think we can add a warning about it since not all systems will have the same limit. Though it is interesting to see Linux hasn't changed theirs for ~15 years. :) Collin [1] https://debbugs.gnu.org/cgi/bugreport.cgi?bug=9191
