Arch Linux

Shaih

Member

Registered: 2016-12-25

Posts: 9

Filesystem and partition size differ [SOLVED]

I noticed recently a 4GB discrepancy between my main arch filesystem on /dev/sda2 and the partition it is on: my partition is 226GB according to fdisk -l, while my filesystem is 222GB according to df-h.

df -h

Filesystem      Size  Used Avail Use% Mounted on
dev             3.9G     0  3.9G   0% /dev
run             3.9G  1.1M  3.9G   1% /run
/dev/sda2       222G  137G   74G  65% /
tmpfs           3.9G  4.1M  3.9G   1% /dev/shm
tmpfs           3.9G     0  3.9G   0% /sys/fs/cgroup
tmpfs           3.9G  988K  3.9G   1% /tmp
/dev/sda1       7.8G  208M  7.6G   3% /boot/efi
tmpfs           787M   28K  787M   1% /run/user/1000

Notice that when using df -h there is 12 GB missing (if you add used and available 12GB is missing to reach 222GB size), this is due to 5% of my fs being reserved and is normal behaviour. Therefore, the 4GB missing are not due to this!

fdisk -l

Disk /dev/sda: 238.5 GiB, 256060514304 bytes, 500118192 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 3785BDD8-2C2D-4828-B9B7-82A5C37FC96B

Device         Start       End   Sectors  Size Type
/dev/sda1       2048   1050623   1048576  512M EFI System
/dev/sda2    1050624 474951679 473901056  226G Linux root (x86)
/dev/sda3  474951680 500118158  25166479   12G Linux swap

After some research i found out this might be cause by the fs not occupying the whole partition, however it is not the case, as shown by the command resize2fs /dev/sda2.

resize2fs /dev/sda2

 resize2fs 1.43.4 (31-Jan-2017)
The filesystem is already 59237632 (4k) blocks long.  Nothing to do!

From what i've seen on other topics and on the wiki, this is not normal behaviour, but i have no idea what could cause this and cannot find anything. Any ideas how to recover my 4GB? I'm quite tight!

Last edited by Shaih (2017-03-26 21:55:44)

2ManyDogs

Forum Fellow

Registered: 2012-01-15

Posts: 4,645

Re: Filesystem and partition size differ [SOLVED]

What does "df -H" (capital H, not small h) or just "df" (with no arguments) tell you?

Last edited by 2ManyDogs (2017-03-26 21:32:34)

HiImTye

Member

From: Halifax, NS, Canada

Registered: 2012-05-09

Posts: 1,072

Re: Filesystem and partition size differ [SOLVED]

What does "df -H" (capital H, not small h) or just "df" (with no arguments) tell you?

that wouldn't be it, 226GB is 210GiB.

the issue is that inodes occupy space as well. disks don't just store data, they also store information about what the data actually contains, and where that data is. those are inodes on Unix filesystems. they occupy around 1.6% of disk space, which for 226GB works out to 3.39GB. you're right around the correct usage, and I'm sure if you removed the -h from df, you'd see a similar max file system size.

Shaih

Member

Registered: 2016-12-25

Posts: 9

Re: Filesystem and partition size differ [SOLVED]

Oh so i guess my units were all wrong: fdisk does not use GB as unit. However this still makes no sense to me:

df -H

Filesystem      Size  Used Avail Use% Mounted on
dev             4.2G     0  4.2G   0% /dev
run             4.2G  1.1M  4.2G   1% /run
/dev/sda2       238G  147G   80G  65% /
tmpfs           4.2G     0  4.2G   0% /dev/shm
tmpfs           4.2G     0  4.2G   0% /sys/fs/cgroup
tmpfs           4.2G  8.2k  4.2G   1% /tmp
/dev/sda1       8.4G  218M  8.2G   3% /boot/efi
tmpfs           826M  8.2k  826M   1% /run/user/1000

/dev/sda2 is 238G while fdisk -l tells me it is 226G... Unless i should factor in the swap (12G), but I don't see why it would be included (according to df man https://linux.die.net/man/1/df )

Same with parted -l and df -h both using GB..

Shaih

Member

Registered: 2016-12-25

Posts: 9

Re: Filesystem and partition size differ [SOLVED]

the issue is that inodes occupy space as well. disks don't just store data, they also store information about what the data actually contains, and where that data is. those are inodes on Unix filesystems. they occupy around 1.6% of disk space, which for 226GB works out to 3.39GB. you're right around the correct usage, and I'm sure if you removed the -h from df, you'd see a similar max file system size.

Ok this explains that. Unfortunately i couldn't find anything searching the web/wiki about that. I'll mark this thread as solved.