Raid one

[Les Mikesell]

Karl Larsen wrote:
>    I did a Goggle search and found Linux Journal, Home, RAID-1, Part 1 
> and 2 by Joe Malmin and Ron Shaker, 2002-08-13 and I have read it like a 
> book once. It talks to the raid-1 being a superior way to back up your 
> computer. I learned that raid mirrors partitions not hard drives. You 
> can use any two hard drives or even the same hard drive! I plan to make 
> a raid 1 using the two hard drives I have in this computer right now :-)
> 
>    One is a 30 GB and this is a 160 GB but f7 is in a partition of 12 
> GB. So I can make a 12 GB partition on the 30 GB HD and make a raid 1 
> system between /dev/hda2 and /dev/hdb5.

It will help your sanity later if you stick to identical disks.

>    The book says if /proc/mdstat exists, you have raid support in your 
> kernel. I do :-)
> 
>    The book set up raid 1 on Red Hat 7 and Debian Potato with the early 
> kernels 8-)

>    It appears I can use the method shown to make a /usr raid 1. I have 
> /usr backed up on my 9 GB USB device. But the author suggests you put a 
> copy of /usr on /var/.  We will use mkraid  which  I find I do not have. 
> Perhaps I can yum it to my system. Perhaps there is a newer tool?

That's outdated.  You don't need anything but the mdadm program - and 
don't follow anything that talks about raidtab.

>     So like all writing it is dated and old just a couple of years 
> later. Instaed of using #init 1 so that /usr can be un-mounted, I think 
> using the rescue mode of the f7 dvd will be easier. Then f7 will be off :-)

It would probably be faster if you can copy everything you want to save 
somewhere else and build the raid during the install, but if you want to 
work at it, you can probably build 'broken' raid partitions on your new 
drive by specifying one of the devices as missing, copy everything over, 
adjust fstab and grub.conf to refer to the new md devices, install grub,
and then swap drive positions.  Once everything is working, you can add 
the old drive into the raid and let it sync.

-- 
   Les Mikesell
    lesmikesell at gmail.com