The zero-fill method (here modified to avoid potential memory bottlenecks) took 17 seconds to create a 10 GB file on an SSD and caused Ubuntu's graphical interface to become unresponsive.

$ time sh -c 'dd if=/dev/zero iflag=count_bytes count=10G bs=1M of=large; sync'

10240+0 records in

10240+0 records out

10737418240 bytes (11 GB, 10 GiB) copied, 17.2003 s, 624 MB/s



real    0m17.642s

user    0m0.008s

sys     0m9.404s

$ du -B 1 --apparent-size large

10737418240     large

$ du -B 1 large

10737422336     large

fallocate creates large files instantly by directly manipulating the file's allocated disk space:

$ time sh -c 'fallocate -l 10G large; sync'



real    0m0.038s

user    0m0.000s

sys     0m0.016s

$ du -B 1 --apparent-size large

10737418240     large

$ du -B 1 large

10737422336     large

truncate also works instantly, and creates sparse files which don't use up actual disk space until data is written later on:

$ time sh -c 'truncate -s 10G large; sync'



real    0m0.014s

user    0m0.000s

sys     0m0.004s

$ du -B 1 --apparent-size large

10737418240     large

$ du -B 1 large

0       large