Question About Drive Mapping - Mint 17 Cinnamon

[Tyerker]

I'll put the tl;dr at the top in case it's a really obvious question.

tl;dr
What does the /mount directory do? Generally wanting to make sure setting a second Steam Library up will mount and function without any problems.


Now for the longer version...
I just recently had Mint 16 start to tell me my SSD was completely full, even after uninstalling most all of my Steam games, and clearing out their respective folders in the home\.steam\steamapps folders. So I figured since 17 just came out, as good a time as any to just blow everything away and start over.

Linux is still housed on my SSD Entirely, with the following Partition Table, all EXT4 format:
/boot: 535MB
Extended Partition :127GB
- Filesystem Root: 30GB
- /home: 92GB
- swap: 5GB

I currently am on a day-old installation of Linux Mint 17 Cinnamon with little more than drivers, updates, Steam and a handful of games. I am definitely needing to install the rest of my games on a secondary Hard Drive.

However, I notice whenever I mount a drive, some data seems to be written / accessed from the main disk in a /mnt directory. Now, forgive me if I'm misreading how it works, but the way it appears to me is that I would not be able to install more games than the SSD would hold in the first place, since the data still has to be mounted and go through my main drive instead of being independent. I have come to this conclusion because when I try to create a new folder / partition on a larger drive (looking at 200GB Partition on my 640GB Caviar Black most likely) it keeps making me choose a mounting point somewhere in my local filesystem.

Again, sorry for my ignorance but why does the mounting point of a secondary Hard Disk have to be on the local disk at all? And how much of that data has to go "through" my SSD's filesystem to get used, and how do I minimize any issues that may go along with that.

I did manage to get TF2 completely functional with FPS Config and HUD in a Linux installation, though, which is fun! I just have too many games to fit them on the SSD, but I like the snappiness of having the OS and main filesystem on the SSD, and some of my online games, or more immersive Single-Player games (TF2, DOTA2, Portal 2, and Metro: Last Light). I can install all my indie games on a slower drive, though, and wait 5 extra seconds to play the game if I need to.

Thanks for any and all help, as always.

 

[su root]

/mnt is an empty directory, designated as a "mount point".

Windows uses drive letters for any new partitions, DVDs, etc that you put into the system. This is good, until you want to mount more than 22-24 devices at the same time.

Linux and Unix systems don't have drive letters. Instead, you choose one partition to be your "root" partition. That is the beginning of your filesystem, "/". On top of that root partition is the LSB directories (Linux Standard Base). That's directories like /etc, /bin, /mnt, /tmp, etc. Each has it's own purpose, allowing developers to follow standards for what kinds of files go in what location.

If you want to access a second partition, you create an empty directory (which is called a "mount point"), and "mount" the second partition there. Mounting takes the entire directory tree of the second partition and connects it to the root partition under that directory. So all of the files and directories on the second partition will just show up under the mount point. If you were to save a file there, it would be written directly to the second hard disk. (It would not be written to the root partition at all -- it would not use up any space there). When you "umount" (or unmount) the partition, it just disconnects the two filesystems, and the mount point goes back to being an empty directory again.

Not everything needs to mount into the root partition though... if we created an empty directory on the second partition, we could mount a third partition there. You can mount a nearly unlimited number of things. However, it gets more powerful than this. I've been saying "partition", but it could just as easily connect a DVD, a NFS or SMB ("windows file sharing") fileserver on your network, an FTP server on the Internet, etc. to your filesystem.

So back to /mnt. According to LSB, /mnt is an empty directory. The purpose of /mnt is a place for (usually temporary) mounting. If I want to quickly mount a DVD, or my file server, I will just use /mnt (or, create a subdirectory in /mnt) as the mount point.

In modern Linux desktop distributions, /media is used as an automount point -- if you insert a DVD or USB disk, it will automatically mount it under /media for you.

If you have a hard disk that you are leaving connected most of the time, instead of using /media or /mnt, you can just create yourself a dedicated mount point for it. It can be anywhere... /stuff /data /mnt/mydisk /steamapps ...then mount it there and add it to your /etc/fstab file.

In your case, even though you have your SSD as your root partition, you can definitely install steam games that are larger than your SSD. Mount your second partition to /steamapps (for example), and in steam, tell it to use /steamapps. Whenever anything attempts to access /steamapps, the system understands that the non-SSD is mounted there, and will write the games there, and not to the SSD.

 

[Tyerker]

OK, this was exactly the answer I needed. I kept thinking that having that drive in my tyerker/media directory was going to take up space on my SSD, but I understand now it's pretty much just a place in the filesystem for the system to look initially, that then redirects it to the actual hard drive being mapped.

I may try to set up a direct mount point, instead of inside Media like I have been.
Additionally, I have all of my pictures, videos, music etc on a separate drive as well (for the sake of space). Is there a way to auto-mount that disk at bootup, so my wallpaper doesn't continuously default back to the Linux Mint wallpaper, and then I have to mount the media drive, and set the desired image as wallpaper.

Thanks for the excellent info!

 

[su root]

Just add it to your /etc/fstab file with the "auto" option (which is default).

https://en.wikipedia.org/wiki/Fstab