I run Ubuntu Netbook 10.04 on my EeePC 1005HA. I'm going to get a SSD for it eventually, but I can't afford one right now so it's running from a 200GB hard disk I scavenged off a dead laptop.

I went in power management and set the option that says "spin down hard drives whenever possible", but this accomplished a whole lot of nothing - whenever the computer is on, the drive's spinning. I ran hdparm -y and the drive clicked off, and then promptly spun back up after a few seconds. Iotop shows occasional tiny bursts of activity from "jdb2/sda1-8", which I don't really know how to interpret, but I don't have anything weird installed so I'm assuming this is normal system operation.

Now, what I need is some sort of application, utility, command - anything - that forces the computer to keep all filesystem changes in RAM with the drive shut down; every five/ten minutes or so (this would hopefully be configurable) it spins up the drive, dumps the filesystem changes to it, and spins it down again.

I realize this presents data loss risks related to crashing and poweroffs when the cache hasn't been dumped to disk, but I'm willing to risk it as Linux never really crashes at all, and since it's a netbook power failures won't cause unexpected shutdowns.

Does such a thing exist?

Thanks.

jdb2 is the journalling block layer - check your (journalling) mount options.

For in-storage filesystems, you'd probably need to roll your own. Several how-to's out there. I doubt you can keep just the changes in-storage.