[CentOS] Question about storage for virtualisation

Mon Jul 2 19:08:31 UTC 2012
Gordon Messmer <yinyang at eburg.com>

On 07/02/2012 11:18 AM, Les Mikesell wrote:
> You aren't done booting until you complete the init scripts for
> runlevel 1.

You may not have noticed, but there is no longer any such thing.  Red 
Hat's init system never booted *through* runlevel 1, the way that some 
other Unix systems did.

Even on older Red Hat systems, /usr is mounted before the runlevel 1 
scripts run.  It's mounted in rc.sysinit.  By your logic, you aren't 
done booting until you have both / and /usr mounted, so there's no value 
in separating them.

> Having to have an extra copy of the kernel on yet another
> device to even get started seems wrong from a minimalist approach, and
> the need for sufficient ram for an initrd even more so.  And you
> really should be able to mount /usr via nfs while retaining
> independent boot/diagnostic capability.

No part of the merge requires and additional copy of the kernel or 
initrd, and I'm not sure where your confusion on the subject originates.

Prior to the merge, you could not reliably mount /usr from NFS, since it 
might not match the libraries in /.  Merging / in to /usr actually makes 
an NFS root filesystem a supported configuration, which was not 
previously the case.

Twice in this message, you've actually argued *for* merging the two 
without realizing it.