Limit Continuous Drive Activity to Power Down HDD

[Constantine A. Murenin]

Hello, 

I run FreeBSD 4.8 at home. I'd like to be able to run the box
continuously, but the HDD is too noisy to leave the system running for
all of the time and specifically for the night.

The BIOS of the motherboard supports automatic HDD shutdown in
XX-minutes of inactivity. However, I have noticed that this doesn't
work as intended with FreeBSD: if I set BIOS to shutdown HDD in two
minutes of inactivity, and then I start FreeBSD without logging into
the system, the disc stops after a few minutes, but it starts again
after less than a few minutes due to some disc activity by FreeBSD.

Out of services, I run apache, dhcpd, mysqld, sendmail, sshd etc. It's
just a home server, so no-one is accessing it all the time.

Is there a way to tweak the system to make it keep all of the
modifications to the filesystem in memory, and not dump them until
some specific time (let's say 09:00) each day, or until the memory is
kind of exhausted? (Clearly, this has a disadvantage of the files
being lost in case the power goes out, so I'll most likely need to
have a UPS.) If something like that is possible, then how do I do
that? I can recompile the kernel with no problems.

P.S. I have a Pentium 4 1.8GHz Northwood on AOpen AX4G-N (i845g+ICH4)
with 256MB DDR266. The HDD is IBM 60GXP IC35L040AVER07-0. There is
plenty of free memory (193MB are usually free upon my first login into
the system after a reboot), and the swap get's rarely used even when
running X with mozilla for a little while. I could probably add more
memory if that'll help (additional 256MB or 512MB, totalling to 512MB
or 768MB).

Thanks,
Constantine.