For my backups I use my own program. On the first run it duplicates
the given directories to an identical structure on the given backup
media. On following runs it compares the previously written backup
structure with the current source and again duplicates the source to
a new identical structure on the given backup media. Only this time
it copies only files which were added or changed. The files that are
unchanged are hardlinked to the previous version, which saves both
time and space, sacrificing redundancy. The program is written in Perl.
I have been using this program since 2013. The backups are nominally
50 GB, but the daily differences are vastly smaller, so that the daily
backup takes about 3 to 4 minutes. The backups use ext2 filesystem.
After I upgraded from fc32 to fc33, the times for the backup have
suddenly risen by a factor betwen 4 and 5. It seems that it is the
writing / linking that takes the additional time. Reading the directory
data doesn’t seem to matter. I did a direct dnf upgrade, so that AFAIK
my FS should still be ext4.
Any ideas? Is fc33 doing some strange transformations from ext4 to
Btrfs and back? Is Perl under fc33 slower? …?