Why is (free_space + used_space) != total_size in df? [migrated]

Posted by Timothy Jones on Server Fault See other posts from Server Fault or by Timothy Jones
Published on 2011-11-28T23:52:49Z Indexed on 2011/11/29 1:53 UTC
Read the original article Hit count: 489

Filed under:

linux

|

ext4

I have a ~2TB ext4 USB external disk which is about half full:

$ df 
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sdc             1922860848 927384456 897800668  51% /media/big

I'm wondering why the total size (1922860848) isn't the same as Used+Available (1825185124)? From this answer I see that 5% of the disk might be reserved for root, but that would still only take the total used to 1921328166, which is still off. Is it related to some other filesystem overhead?

In case it's relevant, lsof -n | grep deleted shows no deleted files on this disk, and there are no other filesystems mounted inside this one.

© Server Fault or respective owner

Related posts about linux

apt-get install and update fail

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I've got a problem with apt-get update and apt-get install ... commands . every time update or installing fails and errors are : Get:1 http://dl.google.com stable Release.gpg [198B] Ign http://dl.google.com/linux/chrome/deb/ stable/main Translation-en_US Get:2 http://dl… >>> More
kernel module compiling error

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
sh@ubuntu:/home/ccpp/helloworld$ make gcc-4.6 -O2 -DMODULE -D_KERNEL_ -W -Wall -Wstrict-prototypes -Wmissing-prototypes -isystem /lib/modules/`uname -r`/build/include -c -o hello-1.o hello-1.c hello-1.c:4:0: warning: "MODULE" redefined [enabled by default] <command-line>:0:0: note: this is… >>> More
Build-Essentials installation failing

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I am having trouble accessing the several critical header files that show to be a part of the build process. The "Ubuntu Software Center" shows "Build Essentials" as installed: Next I did the following two commands, which did not improve the problem: ~$ sudo apt-get install build-essential [sudo]… >>> More
Updating Debian kernel

as seen on Super User - Search for 'Super User'
I'm trying to update my Debian machine to 2.6.32-46 (which is the new stable). However, after doing apt-get update my apt-cache search linux-image shows me: linux-headers-2.6.32-5-486 - Header files for Linux 2.6.32-5-486 linux-headers-2.6.32-5-686-bigmem - Header files for Linux 2.6.32-5-686-bigmem linux-headers-2… >>> More
Serial connection over a single USB cable (Windows to linux, or linux to linux)

as seen on Server Fault - Search for 'Server Fault'
I'm helping out with a project for an embedded device that only has USB and no serial. This device is running Linux. These days, when we need to connect to a serial port on a device we typically use a USB to serial adapter (on something like a phone system or a load balancing device, etc). I would… >>> More

Related posts about ext4

CentOS 5.5 ext4 conversion problem - ext4 partition is recognized as ext3

as seen on Server Fault - Search for 'Server Fault'
Hello. I had 5.4 machine. Upgraded to 5.5 today via yum upgrade. All went fine. Rebooted. Wanted to convert root partition to ext4 (I have three partitions: /boot, / and swap). All of them on software RAID 1 (root is /dev/md2). I did the following for converting yum install e4fsprogs tune2fs -O… >>> More
Is ext4 ready for a production usage ?

as seen on Server Fault - Search for 'Server Fault'
Hi What do you think about ext4 filesystem in the production enviroment ? We are very close to launching our project that will use tens of millions quite often updated not very big files and we need to decide which FS to use. For a while our considerations about other linux FS are: Ext3 is rock… >>> More
Free space not reclaimed after online resizing ext4 in Ubuntu 9.10

as seen on Super User - Search for 'Super User'
My root partition was filling up, with only 500 mbs left, I wanted to resize my root partition from 20 Gb to 40Gb So I resized my partition by using these steps: Using Gparted to resize another partition to give space for the EXT4 Using fdisk, deleting the root partition (on /dev/sda2), and creating… >>> More
Does a ext4 reader for Windows exist?

as seen on Super User - Search for 'Super User'
Is there any software or applications that can read ext4 from Windows? >>> More
western digital caviar black. EXT4-fs error [migrated]

as seen on Server Fault - Search for 'Server Fault'
Recently I update my HDD on desktop machine, and bought WD Caviar Black. But after I format & copy information to it (using dd), and fix partitions size: I have next errors in kern.log: Aug 27 16:04:35 home-spb kernel: [148265.326264] EXT4-fs error (device sdc2): ext4_mb_generate_buddy:739:… >>> More