Snapshots are taken using rsync and hard-links. Common files are shared between snapshots which saves disk space. Each snapshot is a full system backup that can be browsed with a file manager.
TimeShift requires very little setup. Just install it, run it for the first time and take the first snapshot. Cron job can be enabled for taking automatic snapshots of the system at regular intervals. The backup levels can be selected from the Settings window.
Snapshots are saved by default on the system (root) partition in path /timeshift. Other linux partitions can also be selected.
Boot snapshots provide an additional level of backup.
Hourly, daily, weekly and monthly levels can be enabled if required.
Better Snapshots and Rotation
TimeShift runs at regular intervals but takes snapshots only when needed.
Applications like rsnapshot rotate a snapshot to the next level by creating a hard-linked copy. Creating a hard-linked copy may seem like a good idea but it is still a waste of disk space, since only files can be hard-linked and not directories. The duplicated directory structure can take up as much as 100 MB of space. TimeShift avoids this wastage by using tags for maintaining backup levels. Each snapshot will have only one copy on disk and is tagged as "daily", "monthly", etc. The snapshot location will have a set of folders for each backup level ("Monthly", "Daily", etc) with symbolic links pointing to the actual snapshots tagged with the level.
Snapshots can be restored either from the running system or from a live CD. Restoring backups from the running system requires a reboot to complete the restore process.
You can also TimeShift across distributions. Let's say you are currently using Xubuntu and decide to try out Linux Mint. You install Linux Mint on your system and try it out for a week before deciding to go back to Xubuntu. Using TimeShift you can simply restore the last week's snapshot to get your Xubuntu system back. TimeShift will take care of things like reinstalling the bootloader and other details. Since installing a new linux distribution also formats your root partition you need to save your snapshots on a separate linux partition for this to work.
TimeShift is designed to protect system files and settings. User data such as documents, pictures and music are excluded by default. This has two advantages:
You don't need to worry about your documents getting overwritten when you restore a previous snapshot.
Your music and video collection will not waste space on the backup device
Install Timeshift on Ubuntu 15.04
Open the terminal and run the following command
sudo apt-add-repository -y ppa:teejee2008/ppa
sudo apt-get update
sudo apt-get install timeshift