Raid0 bootstrap for ephemeral EC2 disks

ephemeral-setup.sh

# On EC2, /mnt is usually already on
mounted=$(mount | grep /mnt | wc -l)
if [ $mounted -eq 1 ]; then
   umount -l /mnt
fi

# Install mdadm and xfsprogs unattended
DEBIAN_FRONTEND=noninteractive apt-get -y install mdadm xfsprogs

# Create a RAID0 volume with 256KiB stripes, ignore what's already on the device
mdadm --create /dev/md0 --chunk=256 --level=0 --raid-devices=4 --run /dev/sdb /dev/sdc /dev/sdd /dev/sde

# Save the config
mdadm -Es | grep md0  >> /etc/mdadm/mdadm.conf

# Increase the read-ahead
blockdev --setra 65536 /dev/md0

# Create the XFS filesystem, ignore errors tied to ext3 already being there
mkfs.xfs -f -d su=256k,sw=4 /dev/md0

# Now make the volume accessible
mount -t xfs /dev/md0 /mnt