[CentOS] Software RAID and GRUB on CentOS 7

Fri Aug 12 03:18:34 UTC 2016
Rob Kampen <rkampen at kampensonline.com>

On 12/08/16 01:20, William A. Mahaffey III wrote:
> On 08/11/16 02:33, Nicolas Kovacs wrote:
>> Hi,
>>
>> When I perform a software RAID 1 or RAID 5 installation on a LAN server
>> with several hard disks, I wonder if GRUB already gets installed on each
>> individual MBR, or if I have to do that manually. On CentOS 5.x and 6.x,
>> this had to be done like this:
>>
>> # grub
>> grub> device (hd0) /dev/sda
>> grub> device (hd1) /dev/sdb
>> grub> root (hd0,0)
>> grub> setup (hd0)
>> grub> root (hd1,0)
>> grub> setup (hd1)
>> grub> quit
>>
>> I'd like my server to be able to boot a degraded software RAID after an
>> eventual hard disk failure.
>>
>> Any suggestions?
>>
>> Niki Kovacs
>
> I have an aging FC14 (!!!!) system, w/ mdadm RAID partitions. I have 
> /boot setup as mdadm RAID1's, 2 drives (actually partitions). Machine 
> boots AOK, & I believe it does (& maintains) that setup automatically. 
> I got that recommendation from a mailing list ages ago, can't remember 
> where, sorry. $0.02, no more, no less ....
>
>
> [root at Q6600:/etc, Thu Aug 11, 08:25 AM] 1018 # df -h
> Filesystem    Type    Size  Used Avail Use% Mounted on
> /dev/md1      ext4    917G  8.0G  863G   1% /
> tmpfs        tmpfs    4.0G     0  4.0G   0% /dev/shm
> /dev/md0      ext4    186M   60M  117M  34% /boot
> /dev/md3      ext4    1.8T  1.4T  333G  81% /home
> [root at Q6600:/etc, Thu Aug 11, 08:26 AM] 1019 # uname -a
> Linux Q6600 2.6.35.14-106.fc14.x86_64 #1 SMP Wed Nov 23 13:07:52 UTC 
> 2011 x86_64 x86_64 x86_64 GNU/Linux
> [root at Q6600:/etc, Thu Aug 11, 08:26 AM] 1020 #
>
>
I too use this kind of set up. however I do not believe that anything on 
the MBR is updated automatically by any yum/rpm updates. Thus in this 
kind of a setup, one needs to take manual steps.
HTH
Rob