Raid 0 setup doubt.

[Jose Otero <jose.manuel.otero@gmail.com>]

Hello,

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I apologize beforehand if I'm asking a too basic question for the
mailing list, or if it has been already answered at nauseam.
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I have two hdd (Western Digital 750 GB approx. 700 GiB each), and I
planning to set up a RAID 0 through btrfs. UEFI firmware/boot, no dual
boot, only linux.

My question is, given the UEFI partition plus linux swap partition, I
won't have two equal sized partitions for setting up the RAID 0 array.
So, I'm not quite sure how to do it. I'll have:

/dev/sda:

       16 KiB (GPT partition table)
sda1:  512 MiB (EFI, fat32)
sda2:  16 GiB (linux-swap)
sda3:  rest of the disk /  (btrfs)

/dev/sdb:

sdb1:  (btrfs)

The btrfs partitions on each hdd are not of the same size (admittedly by
an small difference, but still). Even if a backup copy of the EFI
partition is created in the second hdd (i.e. sdb) which it may be, not
sure, because the linux-swap partion is still left out.

Should I stripe both btrfs partitions together no matter the size?

mkfs.btrfs -m raid0 -d raid0 /dev/sda3 /dev/sdb1

How will btrfs manage the difference in size?

Or should I partition out the extra size of /dev/sdb for trying to match
equally sized partions? in other words:

/dev/sdb:

sdb1:  17 GiB approx. free or for whatever I want.
sdb2:  (btrfs)

and then:

mkfs.btrfs -m raid0 -d raid0 /dev/sda3 /dev/sdb2

Again, I'm sorry if it's an idiotic question, but I don't have it quite
clear and I would like to do it properly. So, any hint from more
knowable users would be MUCH appreciate it.

Thanks in advance.

JM.