Recently I got a message about "0 bytes free" on a certain partition.

So I looked and, sure enough:

$ df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 65190604 10920296 50959160 18% /
udev 966544 4 966540 1% /dev
tmpfs 389532 744 388788 1% /run
none 5120 0 5120 0% /run/lock
none 973828 152 973676 1% /run/shm
/dev/sda5 397327316 391010276 0 100% /media/8b5e40d0-95b3-4e60-831c-e9b9aeadbfa4

there are 0 bytes available on that partition.

So I deleted a bunch of files I didn't need on this machine, and emptied the trash. I expected the "Used" to get smaller and the "Available" to get larger by the same amount.

But what actually happened was

$ df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 65190604 10921184 50958272 18% /
udev 966544 4 966540 1% /dev
tmpfs 389532 744 388788 1% /run
none 5120 0 5120 0% /run/lock
none 973828 152 973676 1% /run/shm
/dev/sda5 397327316 390986836 0 100% /media/8b5e40d0-95b3-4e60-831c-e9b9aeadbfa4

the "Used" actually did get smaller, but the "Available" is still zero.

I rebooted the machine, and I still see 0 in the "Available" column.

Why is "Available" always zero, even when I delete a bunch of files so "Used" gets smaller?

Why doesn't deleting files increase available space?

I am running Ubuntu 12.04 LTS.

$ df -hi
Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/sda1 4.0M 512K 3.5M 13% /
udev 205K 486 204K 1% /dev
tmpfs 208K 390 208K 1% /run
none 208K 3 208K 1% /run/lock
none 208K 7 208K 1% /run/shm
/dev/sda5 25M 975K 24M 4% /media/8b5e40d0-95b3-4e60-831c-e9b9aeadbfa4

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3 Answers

Step by Step Tutorial

1. Run sudo tune2fs -m 0 /dev/sda5 in a terminal, assuming /dev/sda5 is your drive.
2. Enter your password (you won't see it as you type it).
3. Check your space again, it should be free.

From man tune2fs:

-m reserved-blocks-percentage Set the percentage of the filesystem which may only be allocated by privileged processes. Reserving some number of filesystem blocks for use by privileged processes is done to avoid filesystem fragmentation, and to allow system daemons, such as syslogd(8), to continue to function correctly after non-privileged processes are prevented from writing to the filesystem. Normally, the default percentage of reserved blocks is 5%.

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The simple answer is delete more files. You are seeing the "reserved" blocks reclaiming themselves. Usualy 5% of a filesystem is reserved for privileged processes, is the filesystem is considered full when that limit is reached. You can adjust the limit with the tune2fs -m command. see the man pages for tune2fs for more info.

When you delete a file in a partition that isn't where Ubuntu is installed at, it makes a .Trashes/.Trashes-1000 folder which is the equivalent of recycle bin. The number can differ between Ubuntu versions. Once you are in the partition, press Ctrl+h to see the hidden files which are those that start with .. If you delete this file, then you actually have deleted all the files and you will have more space.

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