Disk setup to boot both RAID1 disks

[Rory Campbell-Lange <rory@campbell-lange.net>]

I wish to configure a server with two SATA connected SSD disks in
software RAID1.

I'm not sure how best to configure the disks for boot, particularly in
UEFI boot mode, to ensure that /dev/sdb can be booted if (for example)
/dev/sda fails.

I have been configuring each disk as follows:

Device     Boot ...   Size Id Type
/dev/sdb1  *    ...   476M ef EFI (FAT-12/16/32)
/dev/sdb2       ... 119.2G  5 Extended              
/dev/sdb5       ...   953M fd Linux raid autodetect -> /md0 (/boot)
/dev/sdb6       ...   1.9G fd Linux raid autodetect -> /md1 (swap)
/dev/sdb7       ...   4.7G fd Linux raid autodetect -> /md2 (/tmp)
/dev/sdb8       ... 111.8G fd Linux raid autodetect -> /md3 (/)
    
I have the following questions:

* is it advisable to have a separate EFI boot partition and separate
  /boot, or are they effectively the same thing?

* is there any benefit at all to having UEFI booting on a pure Linux
  server?

* is there a way to ensure that if there is a grub or kernel upgrade
  that grub-install will operate on both /dev/sda and /dev/sdb?

Thanks for any advice or comments,
Rory