Hybrid Storage harddisks use a large non-volatile cache to save power and improve speed.
I wanted to ask if there's a reasonably simple way to simulate that under Linux. Ideally there would be a FUSE-filesystem that does this, but I would also appreciate hints for writing a homegrown script.
For now this is purely theoretical, but my setup would be a small home server (Sheeva Plug) with an external USB harddisk that goes to sleep after a few minutes of inactivity. To keep it powered down as long as possible, I would like to use a 16GB SD card as a cache for the harddisk, thus simulating Hybrid Storage.
The only possible solutions I found thus far were Hierarchical storage management packages for enterprise use, which are way too expensive for this task...