Setting "Keep history" to zero

[unicast]

Hi.
Can somebody explain, what would happen if I set "Keep history" parameter to zero?
Will be triggers like {.avg(240)}>N works correctly?

Currently I have over 100 hosts with ~80 items each. With "Keep history"=7 I have very hudge load - about 4-5MBps write and 6-7MBps read (postgres delete process).

Thanks in advance.

HW: 2xXeon 3GHz/8GB RAM/RAID-5 6 SCSI 10k drives
SW: Debian GNU/Linux Squeeze, zabbix from debs, 1.8.2

[Ori0n]

I'm surprised your load is that high with only 8000 checks unless you're using a really small poll interval. What is your "Required server performance, new values per second" from Reports > Status of Zabbix?

Setting History to 0 would probably prevent Zabbix from storing anything but the last polled value. So, any trigger based on anything but lastvalue would probably not evaluate as you would expect. In your example, {.avg(240)}, would probably always evaluate to lastvalue because that's the only value stored for the last 240 seconds (assuming your poll interval is <240s).

I really doubt you want to set History to 0

[unicast]

My "Required server performance, new values per second" is 55. Not so high?
Where is bottleneck?

Thanks for explaining about setting history to 0