[CentOS] CentOS 7 install on one RAID 1 [not-so-SOLVED]

Thu Jan 26 09:40:25 UTC 2017
Tony Mountifield <tony at softins.co.uk>

In article <1485416344.2047.1.camel at biggs.org.uk>,
Pete Biggs <pete at biggs.org.uk> wrote:
> > 
> > If you are using RAID 1 kernel mirroring, you can do that with /boot too,
> > and Grub finds the kernel just fine. I've done it many times:
> > 
> > 
> Hmm, OK. I wonder why anaconda doesn't do it then.
> Reading various websites, it looks like grub2 can do it, but you have
> to make sure that various grub modules are installed first - i.e. do
> something like 
>   grub-install --modules='biosdisk ext2 msdos raid mdraid' /dev/xxx
> I don't know if they are added by default these days.

I don't know, but I've never had to do it, when using plain mirroring,
on either C4, C5 or C6.  I can imagine you would need to if /boot was
RAID 0 striped, if indeed that is even possible.

> The other gotcha is, of course, that the boot sectors aren't RAID'd -
> so if /dev/sda goes, replacing it will make the system unbootable since
> it doesn't contain the boot sectors. Hot swap will keep the system
> running but you have to remember to re-install the correct boot sector
> before reboot. If you have to bring the machine down to change the
> disk, then things could get interesting!

Yup, been there, done that. So long as you use grub to install the boot
sector on both drives, then you can always tell the BIOS to boot from
the other drive to bring the system up after replacing the first disk.

Anaconda doesn't set up the boot sector on the second drive by default,
so I put some grub commands in the post-install section of kickstart
to do so.

Tony Mountifield
Work: tony at softins.co.uk - http://www.softins.co.uk
Play: tony at mountifield.org - http://tony.mountifield.org