boot - backup /home folder on different drive through LiveUSB - Ask Ubuntu

i have 2 hard disks: sda & sdb. ubuntu , programs installed in sda, , use sdb store files; sdb half-full.

i’m trying solve booting problem. way system through liveusb, can view both sdx drives.

before radical or stupid, wonder whether use backup tool in liveusb backup system sdb drive. of course, can sudo copy entire /home folder other drive, won’t when i’m able boot or in case decide reinstall ubuntu scratch , need recover old settings.

could here in this?

the backup tool in live disk not complete. it's tricky install necessary components backup working properly. simpler backup /home folder cp command.

you can by, first mount destination backup device (which may mounted since it's /dev/sdb device.

create backup area destination , perform 1 of these 2 commands:

 $ sudo cp -pvau ~/ /mnt/backupdir/ 

in preceding command /mnt/backupdir backup destination directory backing space. create folder username in /mnt/backupdir folder.

this space have been created on partition off /dev/sdb drive.

alternatively backup whole '/home` folder command:

 $ sudo cp -pvau /home /mnt/backupdir/ 

this command result in folder called /mnt/backupdir/home personal home folder under there.

the copy arguments are:

 p - preserve ownership , time stamps v - give verbose output during process - archive (perform recursive copy of files , folders) u - update files have changed if exist in destination. 

you said concerned during "radical" loose personal data.

installing or reinstalling ubuntu not touch /home folder or other folders created on installed partition unless elect format option during installation process. long don't put check mark in format personal data preserved.

it's important have backups of important data. install process advise data erased , not recoverable if select format. if don't checkmark format option, it'll still advise directorys (the system folders) erased , recreated.