It seems that the following items from templates for various OSes that comes with Zabbix 1.6.6 distro are broken:

• Total disk space on $1
• Total disk space on $1
• Used disk space on $1

where $1 stands for (/, /var, /usr, /home, /opt) at least for Template_FreeBSD, Template_Linux, Template_MacOS_X ...

The problem is as follows. They all use non-zero 'Custom multiplier' (equals to 1024) for storing bytes' counter of filesystems. When both Zabbix server and agents versions were 1.6.6 all displays fine (even with this strange multiplier). Values were accurated and close to reality.

A few days ago I've updated Zabbix server to 1.8 version. Agents were still 1.6.6. Values continued to be accurate. Today I've updated agents to version 1.8 too. Shortly later I found that there're misses in collected data. Moreover, Zabbix server began has started to crash. /tmp/zabbix_server.log filled with errors like:

22697:20091214:171041.198 [Z3005] Query failed: [0] PGRES_FATAL_ERROR:ERROR: numeric field overflow
DETAIL: A field with precision 16, scale 4 must round to an absolute value less than 10^12.
[insert into history (itemid,clock,value) values (22794,1260799834,915.458333);
insert into history (itemid,clock,value) values (22569,1260799834,281045.958333);
[skipped]
insert into history_uint (itemid,clock,value) values (23135,1260799837,247813816451072);
insert into history_uint (itemid,clock,value) values (22506,1260799837,2695972782080);

At the same time values displayed in Zabbix frontend were like:

2009.Dec.14 17:13:18 2.4781549417267E+14
2009.Dec.14 17:11:48 2.4781516701696E+14

Used volume size was around 226Gb, so there is amisuse of 1024 'Custom multipler' for counting bytes in templates. I don't no why it worked in 1.6.6.

Once again, Zabbix server 1.6.6 + Zabbix agent 1.6.6 work normal. Zabbix server 1.8 + Zabbix agent 1.6.6 work normal too. But Zabbix server 1.8 + Zabbix agent 1.8 work abnormal if using templates from Zabbix 1.6.6 server (keeped after upgrade 1.6.6->1.8).

Solution: update templates for volume total, free, used spaces by removing custom multiplier. Need to check if it would broke 1.6.6.