Transferring the root filesystem to a ramdisk?
Cordula's Web
cpghost at cordula.ws
Sat Jan 31 06:09:13 PST 2004
Hello,
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 won't need paging, because there'll be enough ram for
everything (ramdisk, kernel and userland).
Now the questions are:
* How to "attach" the root filesystem to the ram disk?
Can this be done only through pxe/netboot before the
kernel starts, or is there some kind of system call
that can transfer root on a running system?
* How to power off (and on) the hdd (both for ATA and SCSI)?
* Will the power consumption decrease (no hdd) or will
it increase (more ram)? Anybody measured this before
with regular diskless machines?
Thanks,
-cpghost.
--
Cordula's Web. http://www.cordula.ws/
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