Subject: Re: [vserver] ramFS Host
From: "Michael S. Zick" <mszick@morethan.org>
Date: Thu, 3 Jan 2008 10:20:34 -0600

On Thu January 3 2008 10:03, Natanael Copa wrote:
>

Thanks!

That sounds very much like what I had in mind.

ramFS/tmpFS - not that much difference when the machine does not have disk swap.
(Since the internal drive is non-replaceable SSD - the machine runs in a "swap off"
state.)
But if the user wanted to keep a SDHC card plugged in - then they could have swap.
Just change the card when (if) it wears out and no touchy when the machine is up.

Mike

> 
> On Thu, 2008-01-03 at 08:30 -0600, Michael S. Zick wrote:
> > Group,
> > 
> > A somewhat abstract question today ...
> > 
> > The usual protocol for a kernel booting with an initial ramFS (early userspace);
> > is for the setup and whatever initialization be done in the ramFS image;
> > then switch_root (which removes the initial ramFS contents) to the "run time"
> > storage media (yea, everyone here knows that) ...
> > 
> > But the size of a truly minimal VServer host image (logging, sshd, ntpd, network
tables)
> > is not very big (target system is a mini-laptop (EeePC) with at least 0.5Gb ram)
- -
> > Why "switch_root" for the host?
> > Why not just bring up the first (most likely only) user context as a vserver on
the
> > run-time media - let the host context continue to run in ramFS?
> > 
> > Technically, it looks like it should work - -
> > Anybody tried this sort of setup?  Any practical problems encountered?
> > Of course, this setup would hold a few Mbytes of disk buffers out of the pool,
> > but the machine has a lot of ram, I don't think they would be missed.
> 
> I do something very similar in my alpine linux distro. Instead of just
> continuing in initramfs, the init script mounts a tmpfs, finds a base
> installation (2-3MB) and "switch_root" to the tmpfs. From here it loads
> a set of packages (from usb/cdrom/cf) and configuration (from
> usb/floppy/cf).
> 
> >From this base installation it is possible to mount disks, raid, iscsi,
> lvm and fire up vserver guests.
> 
> In short you boot from usb/cdrom/cf, run your vserver host from tmpfs
> and run your guests from disks.
> 
> tools are available to save your configuration to floppy/usb.
> 
> http://wiki.alpinelinux.org
> 
> (make sure to boot one of the vsgrsec-* kernels)
> 
> -nc
> 
> > 
> > Mike
> 
> 
>