RAM disk ZFS benchmark for macOS and Linux

ramdisktest.sh

#!/bin/bash
set -euo pipefail

benchmark() {
  # Create a 1000 MiB zero-filled file with DD and write the output to a file to log the speed, then remove it.
  echo "Running benchmark for $1..." | tee -a "$logfile"
  dd if=/dev/zero of="$mountroot/$rampool/$1/test" bs=104857600 count=10 2>&1 | tee -a "$logfile"
  rm "$mountroot/$rampool/$1/test"
}

testkey="$PWD/testkey-$(date "+%s")"         # Location of test key.
logfile="$PWD/ramdisktest-$(date "+%s").log" # Location of logfile.
username=$(whoami)
ramsectors=4194304 # Number of 512-byte sectors to allocate for RAM disk. 2 GiB = 4194304 sectors.
rampool="ram"      # Name of ZPOOL.

# Detect OS and create RAM disk and set mount point
if [[ $OSTYPE == "darwin"* ]]; then
  mountroot="/Volumes"
  ramdisk=$(hdiutil attach -nomount "ram://$ramsectors" | sed 's/[[:space:]]*//g')
elif [[ $OSTYPE == "linux-gnu" ]]; then
  mountroot="/"
  sudo modprobe brd rd_nr=1 rd_size="$((ramsectors / 2))"
  ramdisk="/dev/ram0"
else
  echo 'Error: unknown OS'
  exit
fi

# Create random test key and ZPOOL.
dd if=/dev/urandom of="$testkey" bs=32 count=1
sudo zpool create "$rampool" "$ramdisk"

# Create ZFS datasets and change ownership to avoid running the benchmark as root.
sudo zfs create "$rampool/noencryption"
sudo zfs create -o encryption=aes-128-ccm -o keyformat=raw -o keylocation="file://$testkey" "$rampool/aes128ccm"
sudo zfs create -o encryption=aes-256-ccm -o keyformat=raw -o keylocation="file://$testkey" "$rampool/aes256ccm"
sudo zfs create -o encryption=aes-128-gcm -o keyformat=raw -o keylocation="file://$testkey" "$rampool/aes128gcm"
sudo zfs create -o encryption=aes-256-gcm -o keyformat=raw -o keylocation="file://$testkey" "$rampool/aes256gcm"
sudo chown "$username" "$mountroot/$rampool/"*

# Run benchmark.
benchmark 'noencryption'
benchmark 'aes128ccm'
benchmark 'aes256ccm'
benchmark 'aes128gcm'
benchmark 'aes256gcm'

# Clean up by destroying the ZPOOL and removing the test key.
sudo zpool destroy "$rampool"
rm "$testkey"

# Detect OS and remove the RAM disk
if [[ $OSTYPE == "darwin"* ]]; then
  hdiutil detach "$ramdisk"
elif [[ $OSTYPE == "linux-gnu" ]]; then
  sudo modprobe -r brd
else
  echo 'Error: unknown OS'
  exit
fi