#!/bin/bash

# Author: Alan J. Pippin
# Description: This script will attempt to scrub each zfs pool
#              given to it in the for loop. This script ensures
#              That only 1 scrub operation is running at any given time.
#              This serializes the zfs scrub process for each pool.

maxsleeptime=360
logfile=/var/log/zfs/zfs-scrub.log

for i in tank storage
do
  # Check to see if this zfs filesystem has a scrub being performed on it now.
  # If it does, we cannot perform more than one scrub operation at a time.
  while true; do
    /sbin/zpool status | grep scrub: | grep "in progress" > /dev/null 2>&1
    if [ $? == 0 ]; then
        # Another zpool scrub operation is already running
        # Wait until it is done before continuing
        ransleep=$(($RANDOM % $maxsleeptime))
        sleep $ransleep
    else
        # Another zpool scrub operation is not running
        break
    fi
  done

  date=`date`
  echo "$date: Scrub started for zfs pool $i" >> $logfile
  /sbin/zpool scrub $i
  sleep 60

done