Create separate partition for Postgres

postgres_journaling.sh

# create a separate partition and initialize with ext4
sudo mkfs.ext4 /dev/xvdb

# turn off journaling
sudo tune2fs -o journal_data_writeback /dev/xvdb
sudo tune2fs -O ^has_journal /dev/xvdb

# add to fstab
echo '/dev/xvdb       /mnt/databases  ext4    defaults,auto,noatime,nodiratime,noexec 0 0' | sudo tee -a /etc/fstab

# create the db mount point
sudo mkdir /mnt/databases

# mount the db with settings from fstab
sudo mount /mnt/databases

# move your existing postgres onto the new mount (as of the time of this gist we're using 9.3)
sudo mkdir -p /mnt/databases/postgresql/9.3
sudo chown -R postgres:postgres /mnt/databases/postgresql
sudo service postgresql stop
sudo mv /var/lib/postgresql/9.3/main /mnt/databases/postgresql/9.3

# tweak postgres settings
# change fsync = on -> fsync = off
# change full_page_writes = on -> full_page_writes = off