1) Create directory for the RAMdisk and mount it on boot
mkdir /mnt/ramdisk
#
vim /etc/fstab
  tmpfs           /mnt/ramdisk tmpfs      defaults,size=8192M 0 0
#
#before reboot, manually mount the RAMdisk
mount /mnt/ramdisk

2) Create directory for RRDs backup on the HDD:
mkdir /storage-pool/rrd-pool-backup/

3) Create InitV script (to be moved to SystemD) for RAMdisk control:
vim /etc/init.d/ramdisk

#! /bin/sh 
# /etc/init.d/ramdisk
#

case "$1" in
  start)
    echo "Creating ZFS Pool on tmpfs"
    dd if=/dev/zero of=/mnt/ramdisk/rrd-pool.img bs=128k count=64000
    zpool create rrd-pool /mnt/ramdisk/rrd-pool.img -f
    zfs set compression=lz4 rrd-pool
    echo "Copying files to ZFS Pool on tmpfs"
    rsync -av /storage-pool/rrd-pool-backup/ /rrd-pool/
    echo [`date +"%Y-%m-%d %H:%M"`] Ramdisk Synched from HD >> /var/log/ramdisk_sync.log
    ;;
  sync)
    echo "Synching files from ZFS Pool on tmpfs to Harddisk"
    echo [`date +"%Y-%m-%d %H:%M"`] Ramdisk Synched to HD >> /var/log/ramdisk_sync.log
    rsync -av --delete --recursive --force /rrd-pool/ /storage-pool/rrd-pool-backup/
    ;;
  stop)
    echo "Synching files from ZFS Pool on tmpfs ramdisk to Harddisk"
    echo [`date +"%Y-%m-%d %H:%M"`] Ramdisk Synched to HD >> /var/log/ramdisk_sync.log
    rsync -av --delete --recursive --force /rrd-pool/ /storage-pool/rrd-pool-backup/
    zpool destroy rrd-pool
    ;;
  *)
    echo "Usage: /etc/init.d/ramdisk {start|stop|sync}"
    exit 1
    ;;
esac

exit 0


4) Make InitV script executable and add it to be launched first on boot and last on shutdown:
chmod +x /etc/init.d/ramdisk
update-rc.d ramdisk defaults 00 99

5) Add RAMdisk periodical sync to the Cron:
vim /etc/cron.d/<processname>
  2 * * * * root        /etc/init.d/ramdisk sync >> /dev/null 2>&1

6) Create a directory for Observium���s RRDs and navigate Observium to store RRDs in it:
mkdir -p /storage-pool/rrd-pool-backup/observium-rrd
mkdir -p /rrd-pool/observium-rrd
#root owns the RRD directory in the Observium
vim /opt/observium/config.php
  $config['rrd_dir'] = "/rrd-pool/observium-rrd";