df size mismatch

[Lowell Gilbert]

a.shterenlikht at manchester.ac.uk writes:

> why does df show that used+available < size?
> in my case there is 20M missing for smaller partitions and
> 6GB missing for the larger one. How much can I really use?
> 
> anton
> 
> pw29# df -m
> Filesystem  1M-blocks Used Avail Capacity  Mounted on
> /dev/ad0s1a       247  129    98    57%    /
> devfs               0    0     0   100%    /dev
> /dev/ad0s1e       247    0   227     0%    /tmp
> /dev/ad0s1f     27172 1453 23544     6%    /usr
> /dev/ad0s1d       247    5   222     3%    /var

See "man 8 tunefs" and note "minfree".  Also see:
http://www.freebsd.org/doc/en_US.ISO8859-1/books/faq/disks.html#DISK-MORE-THAN-FULL

-- 
Lowell Gilbert, embedded/networking software engineer, Boston area
		http://be-well.ilk.org/~lowell/