Disk space allocation

[Lowell Gilbert]

Alex Merritt <merritt.alex at gmail.com> writes:

> File systems such as ext3/4 reserve some amount of space for allocation
> only by privileged users, which can be adjusted, e.g.
>
> tune2fs -m reserved-blocks-percentage /dev/sdaN
>
> I installed a BSD system using Virtualbox, giving it an 8GB disk, but 'df'
> shows an aggregate size among all mount points to be less than the
> capacity. The minfree parameter to tunefs defaults to 8% (see below) but 8%
> does not account for the difference in 8189MB capacity vs sum of ca. 6G
> among all file systems (shown by df). There's ca. 27% of capacity
> unavailable.
>
> What could I be missing here?
>
> # fdisk
> [...]
> The data for partition 1 is:
> sysid 165,(DragonFly/FreeBSD/NetBSD/386BSD)
>     start 63, size 16773057 (8189 Meg), flag 80 (active)
> beg: cyl 0/ head 1/ sector 1;
> end: cyl 1023/ head 255/ sector 63
>
> # dumpfs /dev/ad0s1a | grep minfree
> minfree 8% optim time maxcontig 15 maxbpg 2048
>
> # df -hT
> Filesystem        Type     Size   Used  Avail Capacity  Mounted on
> /dev/serno/--.s1a  ufs      620M   140M   431M    24%    /
> devfs                   devfs    1.0K   1.0K     0B   100%    /dev
> /dev/serno/--.s1d  ufs      2.2G   396K   2.0G     0%    /home
> /dev/serno/--.s1e  ufs      248M    10K   228M     0%    /tmp
> /dev/serno/--.s1f  ufs      2.6G   1.5G   882M    64%    /usr
> /dev/serno/--.s1g  ufs      248M   213M    15M    93%    /var
> procfs                  procfs   4.0K   4.0K     0B   100%    /proc

Try comparing to "geom part list".