Date: Thu, 14 Nov 2002 10:54:34 -0500 (EST) From: Jerry McAllister <jerrymc@clunix.cl.msu.edu> To: tcooper1@telusplanet.net (Terry) Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Trying to Dump using Fix it CD (newbie) Message-ID: <200211141554.gAEFsZI18991@clunix.cl.msu.edu> In-Reply-To: <005601c28b86$e9647a70$1baccecd@donatev49iknkl> from "Terry" at Nov 13, 2002 06:38:25 PM
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>
> 1. By doing a dump of / you risk lossing valuable data. Escpecially if you
> have a busy server. It's not possible to take a snap shot other than using
> the fix it CD?
If you are booted to a fixit CD, your server is no longer running.
The only things you would lose would be files that change during or
after the dump is done. Any critical dump of / should be done from
single user (or the fixit). That way, you will lose the least possible
data - probably none, because none of the services that might change
things are running.
> 2. When I use the fix it CD I can't unmount certain devices? For example the
> /tmp directory with nothing in it? I was able to unmount my /backup IDE
> drive. What's the difference between the two?
I don't know what is going on there.
> 3. If I destroy my / directory. How can I mount my other partitions from the
> fixit CD? I can only mount my / slice by using the command "mount /dev/ad0s0
> /mnt"
Well, you will have to make a new root file system - maybe from scratch
if nothing could be dumped. fdisk/disklabel/newfs or use the ones
in /stand/sysinstall
I haven't used this fixit so it may work differently (I don't know how)
but most temporary fixup systems create a filesystem in memory and
put enough stuff there to run the disk building - fdisk/disklabel/newfs
and restore. Things get temporarily mounted in that memory file
system for the restore to run and then the system reboots and all
is well.
It is sort of like if you pulled out your bad disk and put it in a
second slot, put a new disk in the boot slot and built a clean system
on it and used that clean new system to rebuild your old system on
the disk in the second slot. Then when it is all ready, shutdown,
pull the disk out of the second slot and put it in the first and
reboot. It just used a combination of CD and a memory filesystem
for that temporary disk in the first slot.
Actually, if you have the spare disk and the slots to use (nice SCSI
disk cage is great) then do it by bilding a new system on the spare
disk and swapping slots as described above. That's better than using
a fixit CD if you have the resources available. Just make sure you
make the disk in the second slot that your are rebuilding your system
on bootable (presuming a SCSI disk devoted to FreeBSD
fdisk -BI -v -b /boot/mbr da1
(to create the FreeBSD slice and install a standard boot
block - eg no multi-boot manager)
disklabel -w -r -B -b /boot/boot1 -s /boot/boot2 da1s1 auto
(to create initial label on the slice and install boot records)
disklabel -e -r da1s1 (to edit the partitions on the slice)
The man page for disklabel(8) are pretty good at giving examples for this.
(though pretty bad about systematically describing options and flags)
////jerry
>
> I read the hand book and have a text book but if someone has a resource
> using the Fixit program and Mounting devices that would be great.
>
> Thanks in Advance.
>
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