Yes, the /boot partition can be md raid. But it can't be LVM. We're using md raid for all server that have no hardware raid controllers. GRUB can be installed on both drives at the same time, no problem.
Good idea and I think it should be no performance problem. But use LVM! Don't do md raid for each partition you need. Make 2 md raids and put LVM on the 2nd (first for /boot) and use logicalvolumes for your partitions...
I believe that if /boot is on RAID1, that md partition has to be on one of the first two disks (eg hda, hdb)?
Is there any problem with having /boot on a RAID1 partition across 4 disks as follows?
/boot / (LVM) hda RAID1 RAID5 hdb RAID1 RAID5 hdc RAID1 RAID5 hdd RAID1 RAID5
What about swap? It is best on RAID1, RAID5, LVM, something else or doesn't matter?
Mick