bdflush options?? Power-saving...?

[SomeDude]

So i've noticed that my HDD is spinnig up quite often i tried to tune the bdflush options a bit.

i found out what the options in /proc/sys/vm/bdflush do but i didn't figure out which one is the one to fine tune my Harddisk in that way that it spins down after 3 - 4 min and stays that way for at least 1 h if there is nothing going on on the machine. Is it mostly the age that causes it to write out or what is usually the limiting thing (it's a simple fileserver).

Maybe is there another way to prevent the harddisk from writing a few bytes every 6-7 min ??

I use Vcron, but basically to sync time once a day and metalog (haven't done anything to the standart config)