[CentOS] Re: Kernel 2.6.18-53.1.13.el5 fails on network.

[Timothy Selivanow]

On Fri, 2008-02-15 at 07:23 +1100, Steven Haigh wrote:
> > -----Original Message-----
> > From: centos-bounces at centos.org [mailto:centos-bounces at centos.org] On
> > Behalf Of Scott Silva
> > Sent: Friday, 15 February 2008 7:15 AM
> > To: centos at centos.org
> > Subject: [CentOS] Re: Kernel 2.6.18-53.1.13.el5 fails on network.
> > 
> > on 2/14/2008 10:38 AM Steven Haigh spake the following:
> > > I have found the issue with this - and now I feel quite dumb.
> > >
> > > In this box, I keep a second HDD (/dev/hdc) which is mirrored nightly
> > from
> > > the primary HDD (/dev/hda).
> > >
> > > This is an exact copy - initially created via dd, then kept up to
> > date via
> > > rsync on a nightly basis. This is so that if the primary HDD fails, I
> > can
> > > change the system to use /dev/hdc and be up and running  after a
> > > reboot/forced power cycle.
> > >
> > > What was happening is that both /dev/hda3 and /dev/hdc3 have the
> > LABEL=/ -
> > > which means it would be a random guess as to which one got mounted.
> > >
> > > After changing the root=LABEL=/ in grub.conf to root=/dev/hda3, all
> > works
> > > perfectly.
> > >
> > > Man I miss the days when we used device names, not labels ;)
> > >
> > > --
> > Why not do a software raid with the drives? That way it is constantly
> > up to date instead of a nightly rsync.
> 
> Software RAID doesn't help when a different admin installs a package that they shouldn't and overwrites critical files (say the glibc libraries) and hoses the entire system. During the many years of using linux, the most downtime has been caused by humans - not hardware failures.
> 
> Having a nightly rsync between drives allows me to restore the system to a snapshot in a simple reboot. I can then restore to within 6 hours from our remote tape backup system. RAID only helps against hardware failure - not human failure.
> 
> --
> Steven Haigh

Yes, you are correct that RAID doesn't help with human failings.
However, LVM[1], backups, and change control management do ;)


1: http://www.linux.org/docs/ldp/howto/LVM-HOWTO/snapshots_backup.html

--Tim
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