raidcalc

#!/bin/bash

if [ "x$2" = "x" ]; then
    echo "Syntax: $0 disks size"
    exit 0
fi

#			0	1	5	6	10
#Read performance	High	Medium	Low	Low	High
#Write Performance	High	Medium	Low	Low	Medium
#Fault tolerance	None	1	1	2	1/sub-array

echo "Total capacity $(echo "$1 * $2"|bc -l) (disks $1, amount $2)"
# no fault tolerance
echo "RAID0          $(echo "$1 * $2"|bc -l)"

# 1 disk may fail
if [ "x$1" = "x2" ]; then
echo "RAID1          $(echo "$2"|bc -l)"
else
echo "RAID1          only with 2 disks"
fi

# one disk may fail
if [ "$1" -gt 2 ]; then
echo "RAID5          $(echo "($2 * $1) * ($1 - 1) / $1"|bc)"
else
echo "RAID5          minimum 3 disks"
fi

# two disks may fail
if [ "$1" -gt 3 ]; then
echo "RAID6          $(echo "($2 * $1) * ($1 - 2) / $1"|bc)"
else
echo "RAID6          minimum 4 disks"
fi

# you figure
if [ "$1" -gt 3 ]; then
echo "RAID10         $(echo "($2 * $1) / 2"|bc)"
else
echo "RAID10         minimum 4 disks"
fi