I was curious to know how to improve the default backup tool. I saw gzip was CPU bound and thought at proposing pigz as a replacement, because it’s in fedora repository and doesn’t change the output format, so it’s still easy to decompress for unattended backup restore.
Then, I thought it would be nice to compare with xz because it’s already there, and I remembered reading about someone asking to use zstd, but it was dismissed because zstd isn’t always available in you need to restore your backups in emergency, so I added to the list for more fun.
My conclusion is it would be interesting to use pigz instead of gzip as a default compression filter, using 2 or 3 cores in its command line. This would only require Qubes OS to add this small package in the default installation. There is no drawback, and the output remains a gzip file.
qvm-backup --compress-filter=params has an issue,
params can’t have parameters despite
tar --use-compress-program=params being compatible with parameters. I had to use a shell script with the command in it, like
xz -T 5 --fast and used that script in