I just made some upgrades to my PC, one of which was a new 2TB HDD for storage. The old 1TB works fine but now I’m conflicted as to what to do with them. Originally I was going to use some software like ‘unionfs’ to combine them into one 3TB partition. But people have told me that is ill-advised, since if one HDD fails it takes the other one with it. Should I use the smaller hard drive to store backups and keep it separate? What do you think I should do?
It’s really up to you on what you want to use the hard drives for. You can use them to store personal files, movies, photos, downloads, steam games, lutris games, backups, etc.
1 Like
You can use a strategy I employ for these types of situations, where you want to make use of a spare (healthy) drive, that is undersized compared to your new one.
On your main drive, you’re likely to have separate partitions (and directories), the most important being,
/home/username/
Let’s say the username is jessica, and the obvious owner of the directory is jessica.
Create a separate parallel directory under /home/ named “fleeting”, and make jessica the owner,
sudo mkdir /home/fleeting
sudo chown -R jessica:jessica /home/fleeting
Now add this folder to your file manager’s bookmarks or quick access.
Inside /home/fleeting/, make a few folders based on your usage of acquiring and creating files that are not critical nor sentimental. Files that “if they are destroyed, it’s fine.” Here’s an example,
- Downloads
- ISOs
- NAS Quick Share
- Media Dump
- Random Stuff
You can always “promote” certain downloads by moving them over to your /home/jessica/Downloads/ folder. 
In summary, your main drive (2TB) will contain,
- Your OS, swap, boot, root, the works.
- /home/jessica/ <— your main home folder
- /home/fleeting/ <— your “I don’t care if I lose this” folder
Your old, but still healthy drive (1TB) can act as your backup target for /home/jessica/, while ignoring /home/fleeting/.
Large files and temporary downloads that take up a lot of space under /home/fleeting/ will not fill up your backup 1TB drive. This backup destination can perhaps be mounted under /mnt/backup/ or anywhere of your choice (which you can specify in fstab, or let it be handled automatically by your desktop session.)
Due to the parallel structure under /home/, you can use a clean rsync script (or your favorite backup software) to backup everything from /home/jessica/, and not have to worry about manually excluding particular folders in your home.
Here’s a sample rsync command, that you can invoke manually or automatically with a cron task or systemd unit,
rsync -a -v --progress -H -h -xx --delete-delay /home/jessica/ /mnt/backups/
The trailing slashes are very important! The -v and –progress flags might be pointless if it’s done behind-the-scenes automatically.
Keep in mind the –delete-delay flag will delete any files not found under /home/jessica/, so if you delete them on your main drive, the next time rsync runs it will remove them from /mnt/backups/.
So now you always have a backup of everything under /home/jessica/, and if something happens to your 2TB drive, it doesn’t hurt as much to lose the stuff under /home/fleeting/ since you didn’t bother backing it up (as it isn’t important to you.)
This doesn’t mean your 1TB drive is invincible! So consider the principles of data integrity and backups! 
2 Likes
You could use the second 1TB drive to store Timeshift backups (for system) and other backups of home folder (can’t recommend a tool I don’t backup my home 
, don’t use Timeshift to backup the home it is not made to do that). I see people recommending Back In Time for the home folder, to go with Timeshift for the system.
1 Like
The best idea ever, I’m also gonna try it now
This topic was automatically closed 15 days after the last reply. New replies are no longer allowed.