gzip - redirection or piping?
You don't need to use dd
or piping at all.
</dev/sda gzip >/mnt/sdb1/backups/disk.img.gz
</mnt/sdb1/backups/disk.img.gz gunzip >/dev/sda
I once made a benchmark and found using dd
slower than cat
for a straight copy between different disks. I would expect the pipe to make any solution involving dd
even slower in this case.
Piping involves one more process and one more user-land copy, so it should be more efficient to use redirection.
But I guess that on nowadays hardware & software caching system, it should not make any real difference. Maybe you can have better results using bs=4k
or bs=64k
, since it's the pipe's limit under linux. See this question for more detail about different bs parameters.