James G. Sack (jim) wrote:
Carl Lowenstein wrote:
Could it be done by setting up a mirrored pair between the two drives?
Then at some later time I could break the mirror and unplug the
external drive and put it somewhere for safekeeping.
Yes, this could be done. Just be careful about how you reintroduce the
drive to the system. If you ever add it back into the array it will get
overwritten with the newer copy destroying your backup. But if you just
plug it in and mount it and don't add it to an array it should be fine.
Another future time I could get another external drive and again set
it up as the second drive in a mirror pair. Repeat, storing old disk
drives somewhere until it is time to reuse them.
This is a good plan. Be sure to practice a few times to make sure
everything works as you expect. Unfortunately I have never actually done
this so I can't offer any scripts or howto's.
Is this not what the pvmove command is for?
pvmove is for evacuating all of your data from one drive and moving it
to another. Usually because the drive is dying or for some other reason
you want to remove it from the system.
Tracy is probably the one most likely to have personally performed such
an operation (I haven't).
Unfortunately I have never actually performed the exact operation that
Carl mentions. I generally do backups with bacula. But I have used
plenty of mirror raid systems and see no problem with what he proposes.
Oh, one very important thing to do when using mirrored disks when you
expect to be able to boot off of the disks is to install grub onto each
disk. I recently learned this the hard way when we had the only disk
with grub on it go bad in our mail server. What a PITA.
The gentoo wiki actually has some good recipes which work with all grub
based distros.
Quoting from: http://gentoo-wiki.com/HOWTO_Gentoo_Install_on_Software_RAID
---
If you are using a RAID 1 mirror disk system, you will want to install
grub on all the disks in the system, so that when one disk fails, you
are still able to boot. The find command above will list the disks, e.g.
grub> find /boot/grub/stage1
(hd0,0)
(hd1,0)
grub>
Now, if your disks are /dev/sda and /dev/sdb, do the following:
device (hd0) /dev/sda
root (hd0,0)
setup (hd0)
This will install grub into the /dev/sda MBR, and
device (hd0) /dev/sdb
root (hd0,0)
setup (hd0)
will install grub onto the /dev/sdb MBR. The device command tells grub
to assume the drive is (hd0), i.e. the first disk in the system, when it
is not necessarily the case. If your first disk fails, however, your
second disk will then be the first disk in the system, and so the MBR
will be correct.
--
Tracy R Reed http://ultraviolet.org
A: Because we read from top to bottom, left to right
Q: Why should I start my reply below the quoted text
--
[email protected]
http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
