[nzlug] mdadm and lvm on a live distro?

[Nevyn]

On 3/7/07, Robin Sheat <robin at kallisti.net.nz> wrote:
> On Wednesday 07 March 2007 01:14, Nevyn wrote:
> > the lifetime of a hard
> > drive is much greater than a cdrom drive
> Problem is, when a CD drive fails, you take your disk out and put it in a new
> CD drive. When an HD fails, you need to restore from the backups I'm sure you
> made.

The main problem is that I didn't feel I needed backups. I.e. All the
un-recoverable stuff was on a fully redundant raid array for which I
had no practical way of backing up anyway. The drive that failed was
the system drive. So fixing this should be as easy as chucking in a
new drive, installing the OS and installing any apps I needed. The
problem is that I never threw away the drives that I knew to have
failed. This was a huge mistake because I was under the impression
that I had spares galore. However, a spare is only ever good if it
works. Otherwise you'll end p in my situation. No suitable spares, no
money to get suitable replacements and OS.

It occurred to me that I could probably shrink the file server - i.e.
it's currently using 6 hard drives (sata drives) for a total 1.2T.
Since I had only just upgraded it the space is no where near full yet
so I figured seeing as I'm using LVM I should be able to reduce the
size of them, make sure that the data gets moved onto one of the other
physical volumes (fancy way of saying "hard drive" - though this is a
relative term) and remove one of the disks thus giving me a disk to
install an OS to.

I found this page:
http://www.tldp.org/HOWTO/LVM-HOWTO/removeadisk.html

What they didn't tell you however is that you must have free "extents"
on the physical volume that you want to move the data to.

This is somewhat of a problem. First I have to reduce the file system,
un-allocate the extents and then follow the steps from the page above.
Fan-diddly-tastic. Of course to resize the file system I have to check
the file system first. Fun fun fun. It looks like it's going to take
days. And all for want of an ide hard drive.

I've given up on the cdrom idea just because customizing the 'lil
buggers seems to be a real hassle. I really don't know enough of how
this sort of thing works to make it fully functional. (That and samba
in slax was giving me some REALLY strange results. I.e. users couldn't
access their home directories...)