[CentOS] Help finishing off Centos 7 RAID install

[Simon Matter]

> I've just finished installing a new Bacula storeage server. Prior to doing
> the
> install I did some research and ended  up deciding to do the following
> config.
>
> 6x4TB drives
> /boot/efi		efi_fs	sda1
> /boot/efi_copy	efi_fs	sdb1
> /boot 		xfs		RAID1	sda2 sdb2
> VG			RAID6	all drives containing
> 	SWAP
> 	/
> 	/home
> 	/var/bacula
>
> Questions:
>
> 1) The big problem with this is that it is dependant on sda for booting.
> I
> did find an aritcle on how to set up boot loading on multiple HDD's,
> including cloning /boot/efi but I now can't find it.  Does anyone know of
> a
> similar article?

I also spent (wasted?) quite some time on this issue because I couldn't
believe things don't work so nice with EFI as they did before. The
designers of EFI obviously forgot that some people might want to boot from
software RAID in a redundant way.

I ended up with a similar design than you, my fstab has this:
/dev/md0                /boot                   xfs     defaults        0 0
/dev/nvme0n1p1          /boot/efi               vfat   
umask=0077,shortname=winnt 0 0
/dev/nvme1n1p1          /boot/efi.backup        vfat   
umask=0077,shortname=winnt 0 0

Then in my package update tool I have a hook which syncs like this:

EFISRC="/boot/efi"
EFIDEST="${EFISRC}.backup"

efisync() {
  if [ -d "${EFISRC}/EFI" -a -d "${EFIDEST}/EFI" ]; then
    rsync --archive --delete --verbose "${EFISRC}/EFI" "${EFIDEST}/"
  fi
}

BTW, another method could be to put /boot/efi on RAID1 with metadata
version 1.0 but that doesn't seem to be reliable, it works for some
systems but fails on others according to report I read.

>
> 2) is putting SWAP in a RAID a good idea? Will it help, will it cause
> problems?

No problem at all and I don't want to lose a swap device if a disk fails.
So it's the correct way to put in on RAID, IMHO.

Regards,
Simon