On 2020-04-28 [TU] at 14:18 EDT, Bob Weber <bobrweber@gmail.com> said:According to the manual the -x option is: -x, --one-file-system don't cross filesystem boundaries Question: When you use rsync, do you ever do it on a live, mounted filesystem from within said machine/filesystem (that is, using the same machine)? Or do you do it on a "dormant" unmounted filesystem, either from another machine or from a "live [usb or .iso] utility distribution or boot disk from which you have booted the same machine? Most references to rsync I have seen just seem to accept as a given, that you are doing it remotely, from across a LAN (or across the world). And don't seem to address whether the machine/filesystem they are rsyncing to/from is "live" (mounted), or can/should be unmounted (like it would be when imaging a disk with dd or Clonezilla, for example.
Yes that is the way I use rsnapshot (which uses rsync) ... on a
live system. I do this before an upgrade. rsnapshot copies the
files to a directory under /home. I have a very big /home
filesystem. The files I am interested in are under /usr /etc and
the various bin opt and lib directories. These files will just be
open for reading but not for writing. There are log files and
mail files under /var that may be copied in an open for write
state but I can loose those files if necessary. Also, files under
/tmp and /run may be lost but those directories are usually
cleared on reboot. I do run PostgreSQL but the data files are
under /home (mounted from another partition) ... these are the
kind of files that should be backed up on a "dormant" filesystem
or after PostgreSQL is shut down. I also run several virtual
machines but their files are also under /home.
To restore the rsnapshot backup if I need to I run sysrescuecd. I mount the filesystems on /root/src and /root/dst and use rsync with the correct options including --delete to get rid of any extra files that were just upgraded. I usually use -aHXA --one-file-system --progress for rsync backup options. That way I can be sure the file attributes will be preserved.
A note about borgbackup. I used it a few years ago but I found
that ALL attributes were not backed up. Maybe I didn't use the
correct options. The many options can be confusing. The backup
medium should be a journaling filesystem according to the docs.
rsnapshot just duplicates the file structure of the source so you
can just get one file back if you want rather than having to use
borg to get the backed up file.