Re: moving '/' to a new disk
On Tue, 11 Sep 2001, Rino Mardo wrote:
> i see. i've been using the "--exclude-from FILE" option of tar to avoid
> copying /proc and /mnt itself.
No, way too much trouble and too easy to get wrong. The "l" option is
what you want.
> > With /boot on one disk and everything else on RAID1, your system will
> > survive a disk crash but if the disk that died was the one with /boot on
> > it, you won't be able to reboot. It's not too hard to put /boot in a
> > RAID1 as well.
> >
> why is that? isn't that with raid1 (mirroring) all contents of hd1 gets
> copied to hd2 including /boot?
In Linux Software RAID, the RAID arrays are made up of partitions, not
disks. The person who originally asked the question has /boot in a
separate partition outside of any RAID array.
In the following, RAID means "Linux Software RAID". Hardware RAID makes
the array (of disks, not partitions) appear as one disk to Linux and none
of this applies.
It used to be that you couldn't boot off RAID, so you used to actually
have to have /boot in a partition outside of any RAID array. If you
wanted redundancy you had to make another /boot partition on another
disk and mirror it manually every time you installed a new kernel image
or otherwise changed /boot.
Newer versions of lilo can boot off RAID1, so you can have the root
filesystem on RAID1 without a separate /boot filesystem. If you want to
have the root fs on RAID5, you have to have /boot in its own RAID1; lilo
can't (yet?) boot off RAID5.
As I observed before, even with everything including /boot in RAID arrays,
if the bootloader is installed in the MBR of only one disk and that disk
dies, your system becomes unbootable.
If anyone wants a blow-by-blow account of how to set up Linux so that
everything from the MBR on is redundant, please start by searching the
May, June and July archives of this list for "RAID"; I started a thread
when I was trying to do it. Most of the answers should be in there.
George Karaolides 8, Costakis Pantelides St.,
tel: +35 79 68 08 86 Strovolos,
email: george@karaolides.com Nicosia CY 2057,
web: www.karaolides.com Republic of Cyprus
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