[ale] Software RAID1 rebuild after HDD failure (How to do?)

[Ryan Fish]

-----Original Message-----
From: ale-bounces at ale.org [mailto:ale-bounces at ale.org] On Behalf Of Jim
To: ale at ale.org
Popovitch
Sent: Saturday, July 01, 2006 2:13 AM
To: Atlanta Linux Enthusiasts
Subject: Re: [ale] Software RAID1 rebuild after HDD failure (How to do?)

Ryan Fish wrote:
> Now I'm lost on what and/or when to format/not format.  If I build the
> partitions and let either raidhotadd or mdadm reassemble the array
wouldn't
> formatting blow away all of the information that was just put in place on
> the new HDD?  I must be missing something here...

Correct. Do NOT re-format the partition(s).  Just partition the new 
drive with fdisk (fdisk /dev/hdd or fdisk /dev/hdc) and then raidhotadd 
each new partition to the correct /dev/mdX where mdX will be "md" and a 
number that corresponds to entries in /etc/raidtab.  Again, make sure 
you set the partition type to "fd" (auto raid detect) when using fdisk.

-Jim P.
  ------------------

OK, so...

1) Physically replace drive
2) Create partitions (make sure type is "fd", probably don't need to specify
"a" on mirror of /boot but might not hurt either)
3) Use raidhotadd or mdadm to rebuild arrays (md0, 1 and 2)

A co-worker is donating a spare HDD he has so I can test this out at home on
my CentOS box.  I figure it doesn't matter TOO much if I blow it up...


Thank you
-Ryan