Ubuntu
gnome-system-monitor package

Available Space vs. Free Space?

Asked by Nick W

In the 'File Systems' tab, there are columns for both 'Free' and 'Available' space. What is the difference? And how can I make more of my 'Free' space available?

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Michael Bienia
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Best Michael Bienia (geser) said : 		#1

The ext3 filesystem reserves an amount of the total space for root. If some user (or daemon) fills the disk then a login couldn't be possible anymore. So even root couldn't login anymore to fix it. Therefore ext3 reserves an amount of 5% (default) of the filesystem for the root user to prevent it (it doesn't work if root fills the disk).

Available space is now the total free space including the reserved space for root.
Free space is the free space that you as a user can fill :)

It is possible to change this with tune2fs (PLEASE consult the manpage before using this tool).

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Nick W (nick-wiebe) said : 		#2

Thanks Michael Bienia, that solved my question.

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Nick W (nick-wiebe) said : 		#3

Thanks for the quick response. I think something must be reversed though, as I always have more free space than available space.

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Cesare Tirabassi (norsetto) said : 		#4

Yes, available is what you have available as a user. Free is the "physical" free space (which includes the 5% for the su).

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RUSL Bicycle (bikerusl) said : 		#5

Thanks for posting this. I had the same question. Does anyone know how to query tune2fs or fsck so it will tell you the existing fsck interval/reserved space/all that info. I figured out how to 'tune' my reserve space from the man page but I am wary about changing the tune2fs -c or -i because I don't know the current setting. I find the default settings are good and safe but sort of impractical for very large hard drives like I use.

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Michael Bienia (geser) said : 		#6

From the manpage for tune2fs:
   -l List the contents of the filesystem superblock.

$ sudo tune2fs -l /dev/sda7
[...]
Mount count: 19
Maximum mount count: -1
Last checked: Mon Oct 1 19:17:15 2007
Check interval: 7776000 (3 months)
Next check after: Sun Dec 30 18:17:15 2007

I've disabled the fschk after a number of mounts and let check the filesystem every 3 months.

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RUSL Bicycle (bikerusl) said : 		#7

Thanks Again Michael!

I had seen that in the manpage but I hadn't tried it - because I didn't know what a superblock is! and I suspected that was it... But, I was worried that I might be wrong: might break something. Anyway, you've solved it!

I think I need to set my system to check more frequently than current because I don't reboot often. It seems to me you can set both a mount count and time interval and it will honour whichever comes first?

After I changed the reserved for root percentage (I'm pretty sure root doesn't need 15G just for login) my slocate wasn't working for a file I knew was there. I thought maybe I'd changed the file structure with tune2fs and that was why. Then I realised it was in a .hidden folder... Anyway, I'm still relatively new to linux - only a year and a bit with ubuntu. I have fortune running. It tells you some random quote every time you open a new terminal prompt. That same day it came up with: You never learn anything doing things the right way!