Transferring the root filesystem to a ramdisk?

[Cordula's Web]

> > in an attempt to save power on FreeBSD servers, I'm
> > trying to replace the hdd with a ramdisk. The idea is to:
> >
> >   1. boot from the hdd (or netboot from an NFS server)
> >   2. configure a ram disk (md(4))
> >   3. copy everything that's needed to ram disk
> >   4. transfer kernel root to ramdisk (*)
> >   5. turn off the hdd (**)
> >
> > (*) is the hairy question.
> > (**) How can that be done?
>
> I'm probably in over my head here, but;
> chroot should change the root filesystem for you.
> (look in the manpages for more details)

Nope, chroot(2) affects only the calling process, not the whole
system.

> As for powering down the hdd I did find a page for this,
> but havent had time to play with it yet:
> http://www.cran.org.uk/bruce/software.php

ATAidle is great. Just tried it successfully on a 5.2-RELEASE
with two drives. powering down the inactive drive (not the one
with swap and root-fs) is possible this way.

Thanks,
-cpghost.

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