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Re: Disk mirroring

evan.day@home.com wrote:
> You might look into the kernel software RAID if you're running kernel
> 2.4.x.  It supports RAID-1, which is mirroring.  Although mounting a

Yes, I'm running on 2.4.x.

> disk and doing a manual copy would work, in the event your system disk
> fails you'd be stuck with an unbootable system.  With a RAID, you can
> failover to the second disk and continue running while you work on
> replacing the failed disk, then resync everything automatically.

This sounds good.
Then what tools can I use to set it up? (Assuming that kernel support
for RAID-1 is done).
BTW, the controller is SCSI, not RAID; I don't think that I'd be able to
hot-swap the disk. This sounds really interesting; failover just like
that...? And then resync...? Wow.

But the above "fail" means the disk is no longer usable right? What
about the /dev/sd<x> thing? If the first one fail, would the second
still be /dev/sdb? My concern is what's in /etc/fstab. Besides, that
failover sounds like going to work for data disks. I'm talking about
system disks here.

What I have done is to create a single partition on the second disk (my
swap is on a file), copy all the / files into it (using cp -avf), and
then create a new entry in the Grub's menu.lst (which resides on the
first disk); hoping that there would be no (hardware) disk failure. I
think this would cover me on events like filesystem failures. I use
ReiserFS, BTW. It's _way_ fast, but even in 2.4.x it's not considered as
stable. The machine has been up for about 7 days; the last reboot was
due to out of swapspace, I believe. Or some holes on the swap partition
(I have put it on a file, recently).

Another thing, is there any way to chroot apt-get? I'd like to install
new packages, on the second disk, but using /mnt as the root directory.


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