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Re: Plans for upgrading to woody & ditching HD



Thanks to all for the comments. I had assumed that /dev/hd* simply started
at a and incremented by 1, but am happy to know the two IDE channels are
separate.

Karl, thanks for the cautious tips -- I'll pay attention to them :). Note
that / and /boot are on hdb, not hda, so there's literally nothing on that
disk in use except the MBR.

I'll let you know how it goes.

ap

----------------------------------------------------------------------
Andrew J Perrin - http://www.unc.edu/~aperrin
Assistant Professor of Sociology, U of North Carolina, Chapel Hill
clists@perrin.socsci.unc.edu * andrew_perrin (at) unc.edu


On Mon, 13 May 2002, Karl E. Jorgensen wrote:

> On Mon, May 13, 2002 at 09:48:49AM -0400, Andrew Perrin wrote:
> > Greetings-
> > 
> > I have a machine currently running potato. It has four IDE drives in
> > it. /dev/hda does nothing important; it's an old (probably 1993 or
> > 1994) 1.2G whose sole role in life at this point is to have an MBR with
> > LILO to boot DOS, NT, or (99% of the time) Debian.
> > 
> > That drive is quickly dying, and when it dies it brings down the IDE bus
> > and therefore the system. So I need to get rid of it. I'd like to upgrade
> > to woody at the same time.  
> 
> If I was doing that, I would prefer to keep the woody upgrade separate
> from moving disks around. Take a break in between, so you can ensure
> that everything is working OK (= food & drink) and do a backup. One
> thing at a time.
> 
> By the way: If in any doubt whatsoever: keep off-line backups :-)
> 
> > Here's my plan; any comments or advice are welcome.
> > 
> > 1.) Back up /etc to somewhere safe
> > 2.) Edit /etc/fstab:
> >   change all references to /dev/hdb* to /dev/hda*
> >   remove references to (unused) filesystems on what is now /dev/hda
> >   change references to /dev/hdc* to /dev/hdb*
> >   change references to /dev/hdd* to /dev/hdc*
> 
> As others have mentioned, you need not worry about hdc & hdd.
> 
> > (cdrom and zip drive are SCSI so not relevant to this process)
> > 3.) Edit /etc/lilo.conf to point linux to /dev/hda instead of /dev/hdb
> > 4.) Write /etc/lilo.conf to the MBR of the current /dev/hdb (about to
> > become /dev/hda). THIS IS THE STEP I DON'T KNOW HOW TO DO.
> > 5.) Power down
> > 6.) Remove current /dev/hda
> > 7.) Rejumper current /dev/hdb as master
> > 8.) Power back up
> 
> What about this plan instead? It's longer and probably slower, but *I*
> would feel more comfortable with it, as each step can be (relatively)
> easily double-checked. But most importantly: It will be relatively easy
> to go back as well:
> 
> [ Disclaimer: This stuff is Not Tested. Read, validate and make sense of
> it (!) before applying it. Keep backups. ]
> 
> 1)  Make sure that all data on /dev/hda is copied away from /dev/hda:
>     - /boot should copied to /dev/hdb (if it is a separate partition)
>     - / should be copied to /dev/hdb (rsync?)
>     As you have guessed, the idea is to create duplicate file systems.
> 
> 2)  /etc/fstab: Change all references of /dev/hda* to /dev/hdb*
>     depending on where the partition has been copied to. Apart from / and
>     /boot they *could* be copied to one of the SCSI disks.
>     (Here we're talking about your existing root filesystem, not the
>     copy...)
> 
> 3)  Add a few lines to /etc/lilo.conf so you can boot from /dev/hdb *as
>     well* as your current config.
> 
>     (Again, this is done to your *existing* root filesystem; so your
>     copied of the root file system still says /dev/hda* in lilo.conf...)
> 
> 4)  Make a boot floppy with your current kernel with lilo (e.g. via the
>     mkrboot package). Anything that allows you to choose the root
>     filesystem, before accessing the IDE drives will do.
> 
>     [ I don't know how to get lilo to write the boot sector to /dev/hdb;
>     but I *do* know how to use a floppy. Besides, when messing with the
>     boot block, it's nice to know that you can *always* get back in
>     again curtesy of the floppy... ]
> 
> 5)  Test out that you can boot from the floppy and select either root fs.
>     You need to have the option of supplying "init=/bin/bash" to the
>     kernel too.
> 
> 6)  shut down. Remove /dev/hda, rejumber /dev/hdb as master. Assemble
>     things back, and look for loose screws. (where *do* they come from
>     anyway?)
> 
>     You *could* also re-jumber the dying IDE drive as slave and plug it
>     back in.  Perhaps it won't hang the IDE bus when it is not being
>     used? It might be handy to have access to it, just in case something
>     isn't right. But it will also add to the confusion, since /dev/hda is
>     now /dev/hdb and vice versa...
> 
> 7)  Power on, and boot from the floppy, and select /dev/hda* as the root
>     file system, and init=/bin/bash.
>  
> 8)  Modify /etc/fstab: (here we will be on the *new* root file system)
>     # mount -oremount,rw /
>     # vi /etc/fstab
>             change references to /dev/hdb* to /dev/hda*
>     # # If /boot is a separate fs, make sure it is mounted
>     # lilo
>     # mount -oremount,ro /
>     # # umount any other filesystems you mounted
>     # sync ; sync; sync ; # Repeat ad infinitum :-)
> 
> 9)  Hit the reset button (or cycle power) and watch your updated system
>     come up. If everything is OK, it should look and feel idential to
>     before (albeit with one less disk, depending on whether you plugged
>     the dying IDE drive back in).
> 
> Once you're satisfied that everything is working OK, then you can embark
> on the woody upgrade (after the obligatory backups! You can never have
> enough!).
> 
> 
> > 
> > ---At this point I *hope* to have the old system (potato) up and running
> > without the dead disk.---
> > 
> > 9.) edit /etc/apt/sources.list to point to testing instead of stable
> > (should I use woody instead of testing?)
> > 10.) apt-get update
> > 11.) apt-get install apt apt-utils
> 
> I believe that dpkg is updated too (and apt-utils is optional after
> all). And apt-listchanges is handy too:
> 
> 11.) apt-get install apt apt-utils dpkg apt-listchanges
> 
> (This may pull in a new version of libc, so look for any system
> instability after that; things core dumping etc).
> 
> > 12.) apt-get dist-upgrade
> 
> Again, being (very?) conservative, I'd prefer something like this:
> 
> 12) apt-get --download-only --yes dist-upgrade
> (I hope you have a relatively fast internet connection...)
> 
> 13) apt-get --simulate --show-upgraded dist-upgrade
> 
> Review what will be done. Keep an eye out for packages that you consider
> important (or important to your users). The truly paranoid may want to
> take it one package at a time and use the command line above as a
> "what's left-to-do-list". It will be long though...
> 
> > What, if anything, am I missing, or should I be worried about?
> > 
> > Thanks.
> 
> Backups. Backups. Backups. Think each step through before you take it,
> and make sure that you can go back again. You'll walk slower that way,
> but you're more likely to get there in one piece...
> 
> -- 
> Karl E. Jørgensen
> karl@jorgensen.com
> www.karl.jorgensen.com
> ==== Today's fortune:
> The only person who always got his work done by Friday was Robinson Crusoe.
> 


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