raid-one

[Les Mikesell]

Karl Larsen wrote:

>> It can be harder than this, though. Consider what happens after you 
>> have been doing this for a while and are re-using disks that already 
>> have auto-detect md devices on them and/or filesystem labels that may 
>> conflict with ones you are using.  Some of the quirkier disk 
>> controllers can also map a volume into the position where it was 
>> configured, even if you move it or move to a different machine.  You 
>> might pull a disk from the 2nd position on one machine, move it to the 
>> first position on a different machine and add an unconfigured disk in 
>> the 2nd position and have the 2nd drive come up as /dev/sda.
>>
>> But, as long as your new drive hasn't been used, an 'fdisk -l' will 
>> show you which does not have partitions.
> Les you must have had a real hard time with something. I have not moved 
> a hard drive in 4 years. I don't need to do that here at home. When I 
> was working years ago I hired a expert to do all those things. I could 
> still hire an expert but have more fun learning to be one.

I'm supposed to be the expert...  Things are a little different when you 
  need to keep hundreds of old machines running all the time plus 
keeping up with all the new stuff.  I swap disks around all the time and 
a lot of them had linux raid and labeled filesystems in their previous 
use too.  For a long time, fedora would refuse to boot if grub.conf or 
fstab mentioned a label that was duplicated - and installs used the same 
label names every time so duplication was almost certain.  Something 
just smells wrong about that - or any form of second-guessing which disk 
is which.

-- 
   Les Mikesell
    lesmikesell at gmail.com