Can I Rebuild / and /usr Remotely? Ideas?

Jerry McAllister jerrymc at clunix.cl.msu.edu
Tue Sep 20 11:28:31 PDT 2005


> 
> On 9/20/2005 10:20 AM Jerry McAllister wrote:
> 
> >>When I built this system, I configured the disks using sysinstall.  I 
> >>used the "dangerously dedicated"mode just as I had when I ran the 4.x 
> >>series.  I suspect my problems occur because geom_stripe doesn't get 
> >>along well with disks that are "dangerously dedicated". 
> >>
> >>Anyway, my system has 2 9gb drives (da0 and da1) that I wish to use for 
> >>the main system.   I want a 500mb slice as /dev/da0s1a for '/', a 500mb 
> >>slice as /dev/da1s1b for swap, and the rest of each drive as 
> >>/dev/daXs1d.  I will build my stripe with /dev/da0s1d and /dev/da1s1d 
> >>and mount it at /usr.  Other directories such as /var, /home, etc. will 
> >>be symlinked to /usr/var, /usr/home, etc.
> >
> >I would be inclined to want some swap on da0 - the boot drive - too, but
> >I guess you don't have too.
> >
> What would the advantage be?  My thinking is to put root on one and the 
> same size swap on the other leaving two equal sized partitions (or are 
> they slices? I'll never get that straight) with which to build my stripe 
> set.

Just always the feeling that I should be adequately functional at least
to be able to work on fixing things with only one drive available.
Actually, I would put swap on both  da0s1b = 500MB and da1s1b = 1GB.

> >>I have another disk on the system (ad0) that is available and large enough 
> >>to hold the contents of both da0 and da1.  Can I backup my system, do 
> >>the needed operations on da0 and da1, restore da0 and da1, reboot, and 
> >>still have a working system?  I've never used fdisk, bsdlabel, newfs, 
> >>and whatever else I might need from the command line.  Besides the man 
> >>pages, are there any guides for what I want to do?  Even a simple "first 
> >>this, then this, then this" type of guide will help me get started.
> >
> >As long as there is room on the ad0 drive for all of the dumps there
> >should be no problem.    There will be a dump file for each current
> >file system.   You may also need to have some space to unroll a dump
> >if the way you are breaking up the file system in to parts with links
> >is different than the way it is now.   for example if you take /usr/local
> >out our /usr and put it in its own space, you will first need to restore
> >all of /usr somewhere (maybe in its new space if there is room or on
> >the ad0 drive if there is not) and then transfer the separate parts to
> >their new homes - probably using 'tar -cpf'.
> >  
> >
> I'm happy with the layout now but needing intervention on each reboot is 
> not acceptable to me.   This is the only reason I'm considering this 
> exercise.
> 
> >The main thing is to think out the pieces - what each file system is and 
> >what order you will need to restore things so the each new file system 
> >is created and ready and the mount points are there when you need them. 
> >  
> >
> Thank you for your reply.  This gives me some direction in which to 
> proceed.  Since the layout is as I like now, it seems to me that I would 
> only have to dump / and then dump /usr.  The restore order would be 
> first / then /usr.  Is that correct?  Here's my current fstab:

Sounds right from what you indicate here.

////jerry

> 
> blacklamb# cat /etc/fstab
> # Device                Mountpoint      FStype  Options         Dump    
> Pass#
> /dev/da1s1b             none            swap    sw              0       0
> /dev/da0s1a             /               ufs     rw              1       1
> /dev/stripe/data        /usr            ufs     rw              2       2
> /dev/acd0               /cdrom          cd9660  ro,noauto       0       0
> 
> Thanks,
> 
> Drew
> 
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