Large RAID 10 vs small RAID1

RAID is still one of the gray areas of bootloaders IMHO.

I recently built a RAID1 system and after a few hours trying to get LILO/GRUB/GRUB2 to detect my raid i gave up and just told it to use the first partition of the first HDD detected and made sure that if a HDD failed the next HDD was already lined up with the correct MBR/bootloader ect...

So what it does is it boots, grabs the kernel and initfs off the first HDD (no raid) and then boots the kernel and leaves all the RAID stuff to the kernel. Because GRUB/LILO do not physically write to the drives this wont damage them.

Basically i just ignored RAID all together for the bootloader stage.

the kernel needs to re-assemble the raid arrays even if grub does it first. there's no real reason for grub to need to be raid aware for a RAID1 system unless a drive fails during boot.

P.S. You dont need to raid0 SWAP, this ability is already in the kernel. Just set the priority for both swap devices to 1 in FSTAB

/dev/sda2         none                    swap  sw,pri=1        0 0
/dev/sdb2         none                    swap  sw,pri=1        0 0
ect....

And if a single swap drive fails during normal operations there's a very good chance your system will fail. (you can raid1 swap, just not from fstab like above)

In practice, MTBF and write cycle tolerances of SSD are estimates not a killswitch. If a SSD is rated for a billion writes, it doesn't die at a billion and one writes. Combine wear-leveling algorithms, things like TRIM or other on-chip garbage collection and two SSDs dying minutes or even days apart from each other because of wear from writes would be rare.

You should be monitoring your hardware for preemptive failures anyway, so even if both disks were failing at the same time, you'd be able to replace both before a catastrophic failure from something like write wear.