Les Mikesell wrote:
Karl Larsen wrote:
Les Mikesell wrote:
Karl Larsen wrote:
RAID is generally used because of a need, rather than simply
because you
can do it. Of course, if you're doing this as a learning exercise,
that's another matter.
Some benefits of RAID, depending on the type, *can* be faster
access to
data spread over more than one drive (though your current system
might
be more than fast enough, making this pointless), or having a spare
drive that *can* let you keep on working when one drive has failed
(mirroring - useful for servers, probably less important for stand
alone
client machines in the home), or increased storage space by using an
array of drives as if they were one big one (which can also be done
using LVM).
No my need is to have a backup in case this hard drive quits
working. I can do this with rsync. But I am getting the data needed
to make a raid-1 and it would be fun to make one just for the
experience :-)
Disk failure is the most likely thing to go wrong, just not the only
thing so you still need some other kind of backups. Raid has the
advantage that you can recover more quickly if you go down at all
(IDE drive failures often hang the computer until you remove them)
and you don't lose the data past the last backup run. Disks are
pretty cheap these days and they fail unpredictably about like light
bulbs. If you want to make things slightly easier, set up a machine
with 3 or 4 disks and don't bother with raid on the system portion
which you can easily re-install. Just add a pair of drives with one
big parition in a raid1 configuration and move your /home to it - or
set it up that way during the install. Then you just have to save
or remember any special configurations in /etc and keep your
important work under /home.
I see the white knuckles part is where your trying to copy, for
example /usr/ from the working f7 to the raid-1 partition for /usr/.
It seems that you can drop clear back to a basic window with
Ctrl-Alt-F1 and use after logging in as root, # cp -at /usr /dev/md6.
This should work fine :-)
Still it is a worry. But I see how to do it. Now to write it down :-D
You left out a couple of steps there. You have to make a filesystem
on /dev/mdxx and mount it in some tmp directory for the copy. Then
you do the copy using the tmp mount point, then add an entry in
/etc/fstab to mount where you want after a reboot, rename the old
directory and create a new, empty one for the real mount point, and
reboot. And you probably want /home instead of /user. With this
approach you don't destroy your existing copy until you know the new
one works. If it fails for some reason (like forgetting to set the
partition types to FD and they aren't detected at bootup), you can
always boot the install cd in rescue mode and fix things or put the
the old directory back.
Yes you have to make a number of partitions on the new hard drive.
Then you have to make the same number of /dev/md1, /dev/md2 ... /dev/mdx
where x= number. You do this with:
# mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sdb1 missing
Read man mdadm and you will see it IS the raid tool.
--
Karl F. Larsen, AKA K5DI
Linux User
#450462 http://counter.li.org.
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