vfs.fs.size[] reporting incorrect sizes (FreeBSD)

[lstewart]

Hi Folks,

Any help on this is greatly appreciated. The values I'm getting from zabbix_agentd do not match those that are reported by the operating system.

From zabbix:
# /usr/local/sbin/zabbix_get -s sh-b8.XXXXXXXXXXX -p 10050 -k'vfs.fs.size[/home4,free]'
11878643712
# /usr/local/sbin/zabbix_get -s sh-b8.XXXXXXXXXXX -p 10050 -k'vfs.fs.size[/home4,pfree]'
8.347343

From the O/S:
# df /home4
Filesystem 1K-blocks Used Avail Capacity Mounted on
/dev/da3s1c 138860928 127260306 491748 100% /home4

Naturally you can imagine this is a bit of a problem. We supposedly have 8% left on that partition but we actually have 0%.

Some host info:
# uname -a
FreeBSD sh-b8.XXXXXXXXXXX 6.1-RELEASE FreeBSD 6.1-RELEASE #0: Sun May 7 04:42:56 UTC 2006 root@opus.cse.buffalo.edu:/usr/obj/usr/src/sys/SMP i386

# pkg_info | grep zabbix
zabbix-agent-1.6,2 Application and network monitoring solution

If there's anything else I can provide that might help please let me know. I'm thoroughly confused by this - it has to be something wrong with zabbix_agentd.

Thank you,
Landon

[Alexei]

From zabbix:
# /usr/local/sbin/zabbix_get -s sh-b8.XXXXXXXXXXX -p 10050 -k'vfs.fs.size[/home4,free]'
11878643712
# /usr/local/sbin/zabbix_get -s sh-b8.XXXXXXXXXXX -p 10050 -k'vfs.fs.size[/home4,pfree]'
8.347343

From the O/S:
# df /home4
Filesystem 1K-blocks Used Avail Capacity Mounted on
/dev/da3s1c 138860928 127260306 491748 100% /home4


The 'df' must be fixed obviously:

138860928 != 127260306 + 491748

:)

[outi]

if exactly 8% is missing, then this is a faq. FreeBSD reserves 8% of space on each disk for usage only be root (housekeeping of ufs).

[lstewart]

Thank you very much. I was not aware of this 8% reserve.