What does "1K-blocks" column mean in the output of df
?
$ df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda7 21181308 19302672 802668 97% /
udev 4070176 4 4070172 1% /dev
tmpfs 815536 972 814564 1% /run
I guess it is the size of a partition in KB?
Does "1K-blocks" mean the size of each block of a partition is 1KB?
Does a "block" here mean the same as a cluster of a file system?
Best Answer
The
1K-blocks
header is the total space available, measured in 1kB units. Historically, and according to the POSIX standard,df
should report the space in units of 512-byte blocks; you can get that output by doing:The "block" here is simply the unit used for the amounts, it is not related to the file system blocksize (or cluster size, if appropriate for the file system involved). For ext2/ext3/ext4 filesystems you can display the file system info with:
(replace
/dev/sda7
with the file system device).Note that if you add The
Used
andAvailable
columns you don't get the total size shown; this is because of blocks that are reserved forroot
as shown in the output ofdumpe2fs
asReserved block count:
. Those blocks can only be used byroot
, the idea behind this is that if a user fills up the filesystem, critical stuff still works and root can fix the problem.