Disk is full - DHCP stops working

[Corbin23]

Hello all,

I fear this may be more of a linux question than PFSense. My web GUI is showing 100% disk usage. /var/squid was full but I have since cleaned it up so that it's down to around 50% but the disk still shows as full. The DHCP server stops working and gives the following error:

kernel: pid 16494 (dhcpd), uid 1002 inumber 336754 on /: filesystem full

Restarting the DHCP service will get it working for an hour or two before it stops working with the same error message.

df -h:

Filesystem     Size    Used   Avail Capacity  Mounted on
/dev/ad4s1a    2.6G    2.4G    2.2M   100%    /
devfs          1.0K    1.0K      0B   100%    /dev
/dev/md0       3.6M     54K    3.3M     2%    /var/run
/dev/ad6s1      58G     28G     25G    53%    /var/squid
devfs          1.0K    1.0K      0B   100%    /var/dhcpd/dev

du -hd1:

2.0K    ./.snap
 11M    ./boot
1.2M    ./bin
 20K    ./conf.default
3.0K    ./dev
4.3M    ./etc
4.0K    ./home
 16M    ./kernels
242K    ./libexec
6.5M    ./lib
 13M    ./root
3.5M    ./sbin
375M    ./usr
 30G    ./var
842K    ./tmp
2.0K    ./mnt
 11M    ./cf
2.0K    ./tftpboot
177M    ./opt
2.0K    ./lost+found
 30G    .

So my question: How can I begin to free up some space on /dev/ad4sla mounted on "/"? If that is indeed what needs to be done.  :-\

[phil.davis]

Here is my top level dir on a test system:

$ du -hd1 /
512B	/.snap
868K	/bin
 16M	/boot
2.4M	/cf
6.5K	/conf.default
3.0K	/dev
 38K	/dist
 14M	/etc
4.5K	/home
512B	/kernels
7.7M	/lib
270K	/libexec
512B	/media
512B	/mnt
512B	/proc
512B	/rescue
5.1M	/root
3.7M	/sbin
512B	/scripts
512B	/tank
656K	/tmp
169M	/usr
 25M	/var
245M	/

The last entry there is only 245M.
Have you got some huge file/s in the "/" dir?

[Corbin23]

Okay I guess I got it figured out. In /var/lightsquid was a bunch of report files dating back 2+ years. I had removed the lightsquid package but the reports were still there taking up the space. Now down to ~25% disk use and no more write errors. ;D

I guess I don't really understand the "filesystem/mounted on:" that is displayed when issuing df.

[phil.davis]

I guess I don't really understand the "filesystem/mounted on:" that is displayed when issuing df.

"Filesystem" is the actual device that contains some dirs and files - an actual partition on a disk (these days "disk" means spinning disk, CF card, SD card, SSD or even memory-resident virtual-disk). That is physical space that can (and does) fill up.
"Mounted on" is the place in the logical dir tree that the physical "disk" appears - e.g. partition "/dev/ad6s1" files are found in "/var/squid"