In short: can the Deflate compression be used only with the zip format (
-tzip) in 7zip?
I want to archive a big directory (hundreds GiB) from a disk to another, while keeping I/O speed the same or better than without compression.
I like the 7z format for a variety of reasons, but LZMA and Bzip2 compressions are too slow even with
-mx=1. I've tried
7z a -mm=Zip -mx=1 -mmt=4 (and
-mm=GZip which uses Deflate too), but I get an argument error after the file scanning phase.
My typical solution would be tar with
.tar.lzo (LZOP), which easily reaches 100 MiB/s single-threaded at default compress rate; or
GZIP=-1. A very fast compressor is lbzip2 with multithreading, but it cannot be run from tar itself.
My source disks typically read at 20 MiB/s, sometimes 100 (with files several MiB big); the target writes at up to 80 MiB/s. So this is the speed the compressor should have, ideally even when single-threaded. Up to 8 cores and 16 GB RAM are available.